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A REPORT 

UPON ^,„.^.„»«»-. 

The Scallop Fishery 



MASSACHUSETTS, 



INCLUDING THE HABITS, LIFE HISTORY OF PECTEN IRRADIANS, 

ITS RATE OF GROWTH, AND OTHER FACTS OF 

ECONOMIC VALUE. 




BOSTON: 

WEIGHT & POTTER PRINTING CO., STATE PRINTERS, 

18 Post Office Square. 

1910. 









Approved by 
The State Board of Publication. 



■^ 



®tie CcmmontDealtt] of ittassactiuBettB. 



COMMISSIONEBS ON FISHERIES AND GaME, 

State House, Boston, Sept. 15, 1910. 
To the Honorable Senate and House of Representatives. 

We herewith transmit a special report upon the scallop fishery 
of Massachusetts, as directed by chapter 74, Resolves of 1906. 
The complementary portion relating to the lobster fishery is 
embodied in a separate report. 

Respectfully submitted, 

GEORGE W. FIELD. 
JOHIST W. DELAl^O. 
GEORGE H. GARFIELD. 



A Eeport upon the Scallop Fisheey of 

Massachusetts. 



The bays, estuaries and tidal flats of IsTew England are prac- 
tically undeveloped as sources of food. The demands and con- 
ditions of an increased po23ulation, far surpassing the dreams 
of the framers of the colonial laws, have in a very great degree 
destroyed the delicately adjusted balance of animal life in these 
waters, and left us only a comparatively barren waste, governed 
by laws far out of tune with the changed conditions. The waters 
are capable of producing for man as much " sea food " as for- 
merly, possibly more, but certainly an enormous increase over 
present supply if the laws could be so amended as to permit the 
cultivation of the bays and shores to the full capacity, after the 
scientific agricultural methods already adopted for increasing 
the yield of the land. 

It is a well-established law of economics that increased popu- 
lation increases the demand for food, with consequent higher 
prices. These higher prices tend to spread to well nigh every 
branch of living expenses. The fundamental method of check- 
ing this undue increase is to increase the supply. We have 
learned to do this in the case of corn, potatoes, wheat and other 
agricultural staples, and (apart from uneconomic and often 
harmful manipulation, of prices by speculators) the increased 
demand brings forth an increased supply. With the supply of 
game, lobsters, fish, clams, scallops, etc., however, we apply the 
absurd practice of limiting the demand by restrictive legisla- 
tion, e.g., close season, size limit, limits upon time of catching 
or upon quantities to be taken each day, etc., rather than seeking 
to augment the supply. If the demand for corn or potatoes 
tends to higher prices, the logical remedy is the production of 



6 THE SCALLOP FISHERY 

more corn and potatoes. We do not call vociferously for a close 
season on corn or potatoes, or for any other law which tends to 
restrict the demand. Measures are taken as quickly as possible 
to augment the supply. 

The necessary increased development of our shellfish supply 
is notoriously prevented by antiquated and inadequate laws. 
Agriculture cannot flourish where the community must depend 
either upon natural yields ("volunteer" crops), or upon fields 
tilled in common by persons whose chief aim is to selfishly 
appropriate the results " before the other fellow " can. 

The capital required for cultivation of the water, aquiculture, 
is far less than that required for successful cultivation of the 
land, while the returns per acre are far greater, both in money 
and in food value of the product. Our shores, therefore, oifer 
remarkable opportunities for the development of shellfish gar- 
dens. Here employment could be furnished for many thousands 
of unskilled laborers, in a healthy and remunerative occupation. 

To secure such desirable results the public mind must be 
disabused of the false idea, almost universally and tenaciously 
held, that the " public rights " of getting shellfish wherever 
they may be found is a valuable and inalienable right. It is 
equally illogical to apply the same reasoning to forest and fruit 
trees, to strawberries, raspberries and cranberries, making these 
the property of the person who discovers and markets them, 
while at the same time making laws which prevent increasing 
the natural yield through cultivation by individual owners or 
lessees. The intelligent public cannot fail, however, to see, 
upon careful and thoughtful consideration, that what has been 
represented to be a boasted blessing is now in fact a veritable 
incubus, impeding further progress, and to this are to be traced 
many of the unfavorable conditions which check the development 
of our fishing industries and the prosperity of our shore dwellers. 

An abundance of " sea food " is a strong attraction to our 
summer visitors. But the supply must be certain, regular, defi- 
nite, readily accessible for quick consumption; available in 
sufficient quantities to meet special seasons of largely increased 
demand ; and produced under unquestionable sanitary conditions. 

Further, the supply of bait for our shore fisheries is an ex- 
ceedingly important item, and should furnish directly large 



OF MASSACHUSETTS. 7 

opportunities for employment, in addition to increasing the 
quantity of sea fish landed upon our shores. 

For these reasons it has seemed wise to the Legislature to 
devote some attention to the questions involved in the very 
obvious decline in the shellfish production along our coasts, 
since this decline affects not alone the shore communities, but, 
to some degree, every citizen of the State. The problem must 
be viewed in its broad aspect. The source and the supply of 
sea food is not solely and exclusively the peculiar asset of the 
seashore town, to be kept forever closed to development. It 
should be truly public, in the sense which our forefathers in- 
tended, i.e., " free to every citizen of the Commonwealth," free, 
not for plunder and destruction, but for intelligent development 
for the increased production of food and wealth. 

Inasmuch as the scallop (Pecten irradians) and the lobster 
(Homarus vulgaris), though formerly exceedingly numerous 
and cheap, have now become merely a delicacy, practically be- 
yond the reach of the average citizen, it seemed desirable to in- 
vestigate for the purpose of suggesting some feasible methods for 
increasing the market supply, before the source is commercially 
exhausted. 

To say that the fault lies in the increased use of these foods 
is but idly begging the question. The fault rather lies in the 
failure to assist ISTature, which is ever ready to respond to 
intelligent and well-directed efforts to increase her bounty. 

The report covers in very considerable detail the facts con- 
nected with the scallop industry. The notable peculiar fact in 
the life history, the weak link in the chain of supply, and, there- 
fore, of greatest importance, is that the abundance and even the 
continuance of the scallop depend chiefly upon the generation 
immediately preceding. Thus, successful fishing depends upon 
the number of eggs laid by the previous generation of scallops. 
The number of eggs laid depends upon how many adults lived 
through the vicissitudes of the previous winter, after escaping 
the dredges of the scallopers. As a general rule, the scallop 
lays but a single litter of eggs, inconceivably vast in numbers, 
but yet only a single litter. It seems surprising that nature 
should, so to speak, rest all on a single throw. So narrow, indeed,, 
is the margin of safety that the excessive destruction of scallops 



8 THE SCALLOP FISHERY 

less than one year old, i.e., " seed scallops," niaj result in com- 
plete annihilation of the future supply, — a condition which 
has occurred in some localities. 

The present report is largely the work of the biologist to the 
commission, D. L. Belding, A.B., and has been carried on upon 
a broad outline laid oiit by the chairman, under whose general 
supervision the work has progressed, in accordance with the 
provisions of the f olloAving resolve : — 

Acts of 1906, Chapter 74. 
Resolve to provide for an Investigation and Report by the Com- 
missioners ON Fisheries and Game as to Scallops and Lobsters. 
Resolved, That the commissioners on fisheries and game be authorized 
and directed to investigate and report upon the life history, feeding and 
breeding habits of scallops and lobsters, and to make any investigations 
Avhich may assist in devising methods of commercial propagation of 
these animals, or of increasing the market supi^ly. The said commis- 
sioners are authorized to establish and adequately protect structures 
and areas of land or water wherein such animals may be kept under 
observation, and to protect animals or material contained therein, and 
to erect or lease such areas of land or water, buildings, boats or other 
structiu'es, as in their opinion may be necessary for the proper pursuit 
of the above objects. Said commissioners may expend for the purposes 
of this resolve a sum not exceeding fifteen hundred dollars a year for 
a period of three years. , 

CHAPTER I. — INTRODUCTION. 

Dr. George W. "Field, Chairman, Massachusetts C ommission on Fish- 
eries and Game, State House, Boston, Mass. 
Sir : — ■ I herewith submit the following repoi't upon the life history 
and habits of the scallop {Fecten irradians). All investigations herein 
were made in accordance with the provisions of chapter 74, Resolves 
of 1906. The work was conducted by D. L. Belding, assisted by W. G. 
Vinal in 1907, 1908 and 1909, and by W. H. Gates and C. L. Savery 
in 1906. 

Respectfully submitted, 

David L. Belding, Biologist. 

The following report embodies the results of the experiments and 
investigations conducted on the Massachusetts coast during the years 
1905 to 1909. The facts discussed in this paper are intended for the 
inspection of three classes of readers : the fisherman, the consumer, and 
the scientific student, each accustomed to the daily use of terms with 
which neither of the otliei's is familiar. This circumstance, added to the 



OF MASSACHUSETTS. 9 

fact that the subject-matter of the report is largely technical in char- 
acter, renders it doubly hard to present the material in clear and com- 
prehensive form. As the investigations were primarily designed for 
the benefit of the fisherman, the terms as far as possible will be those 
used by the practical seacoast inhabitants, while the report is arranged 
so that sections which are purely scientific may be omitted without 
impairing the value of the whole paper. Whenever a scientific or collo- 
quial name is used in the text the common name is either given with it 
or a more complete definition is appended in the glossary. 

The circumstances which led to the legislative act authorizing the 
investigation were briefly as follows : In the years previous to 1905 the 
scallop industry, while still an important source of winter revenue for 
the southern coast towns of Massachusetts, manifested signs of serious 
decline, especially in the Buzzard's Bay region. A natural resource of 
sufficient importance to bring into the Commonwealth a yearly revenue 
of nearly $150,000 could not be neglected, and the result was that the 
Legislature directed the Bepartment of Fisheries and Game to study 
methods of improving the scallop fishery. The laws which were at that 
time in force were based on very defective knowledge of the life history 
and habits of the scallop, and it early became apparent that a knowledge 
of these important points was essential for jjroper legislation for the 
conservation of the industry. It is earnestly hoped that an immediate 
result' of this investigation will be the passage of suitable legislation for 
the i^reservation of the scallop fishery. 

Object. — The aim of this report is to publish all known facts about 
the life and habits of the scallop, and to show their proper bearing 
upon the present fishery. At the beginning of the investigation certain 
important questions of a practical nature presented themselves. 

(1) Is the scallop supply of Massachusetts in danger of extermina- 
tion? If so, hoAV can this be avoided? 

(2) Is the present protective legislation based on accurate knowledge 
of the life and habits of the scallop? 

(3) Can the scallop be propagated artificially? 

(4) How can the present industry be increased? 

In order to obtain satisfactory answers to these questions it was 
found necessary to obtain information upon: — 

(1) The distribution and range of the scallop. 

(2) The anatomy and its relation to the habits of the animal. 

(3) The spawning, reproduction, early life history and propagation. 

(4) The habits of the young and of the adult. 

(5) The rate of growth and length of life. 

(6) The scallop fishery, — its present extent and possibilities. 
Presentation. — Information on the above points, as comi^letely as 

possible, is presented in the following pages, each topic in the form 
of a chapter; and the practical bearing on the four questions is con- 
sidered whencA^er feasible under each subject, and is summarized in the 



10 THE SCALLOP FISHERY 

general conclusion at the end of chapter VI. It is realized that there 
are various facts AA'hieh still require further study, and that it will take 
years of investigation to complete the historj- of the animal. The 
anatomical description in chapter II. is by no means complete. The 
object is merely to give the reader a general idea of the structure of the 
animal, and to make clear the more intricate development of the various 
organs as they appear in chapter III. No claim is made for marked 
originality or for detailed work in the chapter on anatomy; the general 
scheme given by Drew (1) is closely followed, and only a simplified 
description is given. Likewise, the embryology of all the lamellibranch 
moUusks have such a close similarity, not alone in the general course 
of development, but even extending in some cases to very minute details, 
that the description of any species might be applied equally well during 
its early stages to any other closely related species. Thus, although our 
work uiDon Pecten irradians was begun fo^^r years ago, and carried on 
entirely independently, and is, we believe, the only work upon this 
species which even professes to approximate completeness, its general 
features closely parallel the admirable work of Drew (1) upon Pecten 
tenuicostatus (the deep-sea scallop). Many of our results, therefore, 
are entirely new for Pecten irradians, and, since they confirm the earlier 
published observations on this and other species by Drew (1), Jackson 
(4) and others, to whom due credit is given, are of use not alone as 
confirmatory evidence; but since they contribute new observations and 
original applications of these facts to the practical solution of how best 
to develop and maintain our scallop fishery we trust that they are not 
without value. The life history is given in narrative form and is not 
explained in detail, as could be done by sectioning the developing eggs 
and embryos. As it is the purpose of this paper to present not only neAv 
material but also a rather complete account of the life and habits of the 
scallop, it has been frequently necessary to reprint or refer to previous 
works on the subject. In most cases these observations have been 
verified by our experiments, and are printed with the consent of the 
authors. 

Courtesies. — At the start of the investigation in 1906 there was found 
a general lack of knowledge among the fishermen upon such important 
points as the spawning season, rate of growth and length of life of the 
scallops {Pecten irradians). Indeed, little literature on the subject was 
available, Kellogg (5), Jackson (4), Ingersoll (8) and Risser (2) com- 
pi-ising all publications on Pecten irradians. Of these, Risser alone 
dealt with the spawning, gTowth and length of life in his report upon 
the life history and habits of the scallops in Narragansett Bay, Jackson 
with the young scallojD, and Kellogg and Ingersoll with the industries. 
While the paper by Risser was of great as'sistanee at the start of the 
work, the diverse natural conditions in Massachusetts Avaters often ren- 
dered our results at variance, and unfortunately made this excellent 



OF MASSACHUSETTS. 11 

report only valuable for comparative purposes. In addition to these 
publications the following papers proved of special value in the work: 
Drew (1) was of great assistance in studying the embryology and in 
preparing the chapter on anatomy; Jackson (4) furnished considerable 
help and useful methods in tracing the post-embryonic development; 
and Kellogg (6) was found a most comprehensive and valuable paper 
for general reference work. 

The writer is. deeply indebted to Dr. George W. Field for his general 
supervision and helpful advice in the investigations and in the prepara- 
tion of the report; to Prof. James L. Kellogg of Williams College, and 
Prof. Oilman A. Drew of Maine University for their kindly criticism; 
and to the scallop fishermen of Massachusetts for their friendly assist- 
ance. More especially is acknowledgment due to the assistants in the 
investigation. In the summer of 190G W. H. Gates and C. L. Savery 
ably assisted in the post-enibryological investigations and general gTowth 
experiments. During the summers of 1907, 1908 and 1909 W. G. Vinal, 
together with D. L. Belding, brought the embrj'ological and post-embryo- 
logical work to a completion. The work of all three assistants, particu- 
larly the continued investigations by W. G. Vinal, is worthy of special 
commendation. 

Methods of Investigation. — The greater part of the work on the scal- 
lop was conducted at Monomoy Point in the town of Chatham. Near 
the end of this point an enclosed body of water, some 6 acres in area, 
connected with the ocean by a shifting channel through which the tide 
joassed every twelve hours, Avas acquired by the State for experimental 
purposes. This body of water, called the Powder Hole, is a natural 
breeding ground for shellfish, and proved an excellent place to study their 
life history and habits. A few scallops were found in the Powder Hole 
at the beginning of the investigations; more adults were brought there 
for breeding purposes and the basin was transformed into a natural 
aquarium. In this way it was possible to keep close observation on 
several successive generations of scallops in regard to their growth and 
length of life under completely natural conditions. A small laboratory 
was erected on the shore, and a raft 20 feet long by 10 feet wide was 
securely moored in the deepest part of the cove. The raft proved an 
invaluable aid in catching and rearing the young, some of the most 
important experiments being conducted on it. 

While Monomoy was the central station for the scallop work, observa- 
tions were made in other parts of the State under as diverse conditions 
as possible. Records of the spaAvning, growth, migration and habits 
were kept at Edgartown, Nantucket, Chatham, North Falmouth, Marion 
and Monument Beach. In this manner the entire scalloping territory of 
the Commonwealth was under surveillance. Under chapter VII. the 
specific methods of work will be given in greater detail. 

The Scallop Family. — The scallop belongs to the class of mollusks 



12 THE SCALLOP FISHERY 

called the Lamellibranchia, or. to use an older nomenclature, the Pelecy- 
podM. The family of the Pectenidce includes a great many species, 
totalling' about forty, of which the most imjDortant commercially is the 
shallow-water variety, Pecten irradians. Of the four species found on 
the Atlantic coast only two are of commercial importance in New Eng- 
land, Pecten irradians and Pecten teniiicostatus, the giant or deep-sea 
scallop of Maine. These are rivals in the Boston market, but the smaller 
scallop is usually preferred by reason of its more delicate flavor. Sev- 
eral different species of the Pectenidce are used as food in other coun- 
tries. Fossil Pectens have been found as far back as the Carboniferous 
age. 

Names. — Pecten irradians is more commonly given as the scientific 
name for the shallow-water scallop of the Massachusetts coast, but the 
later and more exact title of Pecten gibbus, var. borealis Say., is now 
used. In New England the animal is ordinarily called by the name 
" scallop," sometimes Avritten " escallop." This word, according to 
Ingersoll (8), is derived from either the French " escallope " or the 
Dutch " schelp," meaning a shell. In Italy the scallop is called " cape 
saute," in Holland " mantels," in England " fan shells," " frills," 
" queens," and '' squims." 

Distribution. — Pecten irradians has a wide geographical range, ex- 
tending from Massachusetts Bay to the Gulf of Mexico, where it has 
been reported in the vicinity of the Chandeleur Islands in Louisiana by 
Professor Kellogg (7). It is occasionally found along the Atlantic 
seacoast Avherever the coast is sufficiently broken to afford sheltered 
bays and inlets. In 1880 Ingersoll (8) reports its presence in North 
Carolina, where it was used for local trade at Moorehead City. The 
scallop inhabits quiet waters, where it is protected from heavy winds 
and storms, which would wash it high on the sandy beaches. Long 
Island Sound is very productive of scallops, and many thousands of 
gallons are shipped from its waters in a successful season. 

In Massachusetts this species occurs commercially only in the waters 
south of Boston (Fig. 78). It is usually found in abundance along 
the southern shore of Cape Cod, in Buzzard's Bay and about the islands 
of Nantucket and Martha's Vineyard. According to a map in the 
Boston Museum of Natural History a small bed formerly existed in 
the waters off Nahant. Shells are often picked up on the North Shore 
beaches, but at present no live scallops are found in this State north of 
Boston. It is reported that a few are to be found in some of the warm 
bays of the Maine coast. Thus the scallop fishery in Massachusetts is 
only a partial industry, as it concerns only the Vineyard Sound and 
Buzzard's Bay shore. 

The bathymetrical range of the scallop is extensive, as many thousand 
acres of eel-grass flats, extending even to a depth of 60 feet of water, 
are covered at times with this bivalve. Usually the scallop is found in 



OF MASSACHUSETTS. 13 

water from 5 to 30 feet deep. Scallops are often abundant on the high 
fiats where there remains but a foot or two of water at low tide, as on 
the Common Flats at Chatham. These exposed places with the thick eel 
grass seem to I'eceive the heaviest sets, but the young often jDerish in 
the cold winters. Scallops can arbitrarily be separated into two classes : 
(1) the channel or deep-water scallops, found in water 15 to 60 feet 
deep, and (2) the shallow-water or eel-grass variety, from low-water 
mark to 15 feet. 

While the extent of the scalloping area is large, owing to the wide 
range of the animal, only portions are ever productive at any one time. 
A set may be in one place this year and the next year's spawn may 
" catch " in a diiferent locality. Thus, while all the ground is suitable 
for scallops, only a small part is in jDroductive operation each year. 
The natural barrier to the distribution of the scallop is the exposed 
nature of the coast, as this mollusk cannot live in rough waters. 

CHAPTER II. — ANATOMY. 

The loss of the anterior adductor muscle in Pecten, as shown by 
Drew (1) and Jackson (4), has been accompanied by a shifting of the 
soft parts, so that the antero-posterior axis, instead of running parallel 
to the hinge line, forms with it an angle of at least 60°. While this 
fact is recognized, for simplicity the relation of the hard and soft parts 
in the following description is considered as in a typical lamellibranch. 
The animal is oriented: (1) dorso-ventral axis or height, from the 
hinge to the opposite edge of the shell; (2) antero-posterior axis or 
width, the distance across the shell; (3) lateral axis or thickness, the 
distance between the two valves (Fig. 65). 

The Shell. — The scallop shell consists of two lateral valves joined 
together on the dorsal edge, the hinge line (HIi), by means of a thin 
ligament. The two valves, which open on the ventral or lower edge, 
are nearly round and of equal curvature. The right or lower valve, on 
which the animal rests, is of a lighter and cleaner color and differs from 
the upper in having a byssal notch (B) or foot groove. In the scallop 
less than a year old this notch is lined with several projecting teeth, 
which are absent in the old animal. If the shell of an adult is broken 
along the notch a row of thirty-five or more of these teeth can be seen 
extending back to the umbo. The adult scallop is somewhat wider than 
high, the average dimensions being: height, 2% inches; width, 2% 
inches; thickness, l%o inches. 

On the outer surface of the shell are prominent ridges and furroAvs 
(R, F) which radiate from the beak to the free margin, giving the 
animal a beautiful fan-like appearance. The number of ridges does not 
vary in the individual scallop, the adult having the same number as 
the very young animal. In different scallops the number of ridges 



14 THE SCALLOP FISHERY 

varies from 14 to 19, the average being 16. Crossing the radiating ribs 
are concentric growth lines, which almost show the daily accretion of the 
shell. Age and wear cause these to be less conspicuous toward the beak 
and on the lower valve. During the winter months growth ceases and 
when again resumed in the spring, a heavy line has formed by the 
thickening of the edge of the shell, comparable to the annual ring of a 
tree. This is the so-called growth line, which defines a '' seed " or 
immature scallop. Such marks may not always represent the end of 
the season's growth, but may indicate that unfavorable conditions for a 
certain length of time checked the building processes of the animal. 
When scallops were transplanted from Inward Point to Monomoy 
Point, being confined several days, the change caused a mark similar 
to the annual growth line. 

In old age these growth lines may pile up and form a very slight 
re-entrant in the shell, due to retrogressive development. The re-entrant 
is not so conspicuous in Pecten as in other lamellibranchs which have 
a thicker shell. If the edge of one valve is broken, the opposite valve 
grows down abnormally to protect the soft parts. Both valves are 
needed in place to get a normal growth in the same manner as rodents 
require both sets of incisors to wear on each other. 

Besides these markings the outer surface of the shell may be engraved 
by various enemies. The oyster drill often punctures a small hole in the 
shell and through it sucks out the soft parts. The boring sponge does 
not attack the scallop as frequently as it does the oyster and other 
mollusks which lead a sedentary life, but occasionally parts of the shell 
are dissolved by the secretions of the sponge. In the older scallop of 
fifteen months the upjDer valve is usually covered with various forms of 
life, such as Serpula (worm tubes), barnacles, young oysters, Anomia 
(silver shells), Crepidula (quarter deckers), Acmeea and such sea weeds 
as Enteromorpha, Ulva and Champi parvia. Many old scallops are 
doubtless killed by the accumulation of foreign growth, which at times 
fastens the valves together. 

The inner surface of the shell is very smooth and somewhat vitreous, 
due to the nacreous or pearly material secreted by the mantle. The 
ridges and furrows exist but are not conspicuous. The scar, which 
marks the attachment of the adductor muscle, can be seen indistinctly 
outlined slightly to one side of the center of the shell. 

The hinge line (HH) is curved in most lamellibranchs, but in Peeten 
it is straight, and extends to the end of the well-developed " ears." A 
V-shaped spring in the central part of the hinge tends to keep the 
valves apart after the same manner of doubling a large piece of rubber 
in the hinge of a door. When the animal is at rest the large adductor 
muscle is relaxed and the valves remain open. 

The calcareous shell is formed by the secretions of the mantle. Al- 
though it is added to slightly by the surface of the mantle, the main 
inci'pase is in height and width at llie edge of tlie mantle. These two 



OF MASSACHUSETTS. 15 

secretions differ in structure; the inner pearly or nacreous portion 
being' formed of thin layers, the outer of prisms. The valves increase 
in size as the direct consequence of the increase in size of the soft parts. 

The shell is well adapted to the life of the scallop. Being light in 
■weight it is suitable for moA^ement through the water, while the rounded 
outline is the form which offers the least resistance for swimming. The 
opposite ridges and furrows fit tightly together when the valves close. 
Thus, when the animal moves, streams of water are forced by the aid 
of the mantle through the small openings below the " ears," or from 
the ventral edge of the shell. 

The Mantle. — The shell of the scallop is lined with a thin ciliated 
organ called the mantle (Fig. 73, m). The thickened margins of the 
two mantle lobes are free ventrally but are united dorsally and to a 
slight extent on the anterior and posterior ends in the region of the 
" ears." In a scallop of 52 millimeters the mantle lobes are united 
posteriorly for 13 millimeters and anteriorly for 6 millimeters. This 
corresponds roughly to the width of the " eai's " of the shell, 12 milli- 
meters and 6 millimeters respectively. The shorter union anteriorly 
pei'mits the extrusion of the foot. The free edge of the mantle, often 
brightly pigmented, jjossesses tentacles (t) or tactile organs, and bead- 
like eyes of a bright blue color. These sensory organs are not so 
numerous or so large near the byssal notch and the corresponding 
posterior edge. Each lobe of the mantle is attached to the inner surface 
of the valve about one-half inch from the free edge. The broad face 
of each lobe rests on the inner surface of the shell except when the 
animal is disturbed and the mantle withdrawn by the retractor muscles. 
While resting, the mantle lobes are held slightly apart, the guard tenta- 
cles forming a lattice work between the perpendicular flaps of the 
mantle through which the water passes. As previously stated, the 
mantle also functions in the formation of the shell. 

Tentacles. — The sense organs of the mantle are of two kinds, tenta- 
cles and eyes. There are numerous tentacles near the free edge of the 
mantle, which vary greatly in size and formation. These tentacles can 
be divided into two classes, (1) the mantle tentacles, which are situated 
on the external edge of the lobe in several rows, and (2) the guard 
tentacles, situated on the edge of the perpendicular flap of the mantle, 
5 to 6 millimeters from the edge. Each class differs in form and func- 
tion; the mantle tentacles are larger, capable of greater extension and 
contraction, and armed with papillary projections, while the guard 
tentacles are smaller, less extensible and of a bright color. The tentacles 
have a sensory or tactile function, and when the scallop lies undis- 
turbed, the mantle tentacles, lengthening out, wave slowly in the currents 
of water. They can be withdrawn immediately at the passing of a 
shadow or at any slight distxirbance in the water. When contracted 
each forms a slight conical projection. 

Eyes. — Situated between the band of tentacles and the outer edge 



16 THE SCALLOP FISHERY 

of the mantle are many well-developed eyes, brilliantly lined with 
bine and brown pigment, which help to make the scallop attractive to 
snmmer colonists. When sectioned, these eyes are fonnd to be spe- 
cialized organs eomjj arable to the eyes in the higher animals. They 
vary in size and nnmber, the larger ones usually occupying the grooves 
of the shell, although in the adult definite arrangement appears to be 
lacking. To what degree the eyes react to light and to external stimuli 
is problematic, and offers a field for research. They ajapear to be 
keenly sensitive to any change in light and shade, possibly observing 
the approach of an enemy by its shadow or movement in the water. 

Muscles. — Unlike the soft clam (Mya) and the quahaug (Venus), 
which have two adductor muscles for closing the shell, the scallop has 
only a single adductor muscle (the so-called eye in the fisherman's 
vernacular), which is situated posterior to the center of the shell, form- 
ing a conspicuous part of the internal anatomy. The muscle is made up 
of two parts, a large anterior section and a small posterior division. As 
is shown in the development of the young scallop, this muscle is the 
posterior, the anterior adductor disappearing during the early shell 
stage. The' muscle is the edible part of the scallop^ and its shape is 
maintained when served on the table as " fried scallops." When the 
muscle is cut the valves immediately gape open, being forced apart by 
the V-shaped cartilaginous elastic pad in the middle of the hinge. The 
other important muscles are the retractor muscles of the foot, the gills 
and the mantle. 

Gills. — There are four gills (Fig. 74, g) in the scallop, a pair on 
each side of the generative mass and ventral to the adductor muscle. 
Each pair has a free end posteriorly and extends in a curved line 
nearly around the posterior adductor muscle. The gills are attached 
dorsally near the adductor, the inner and outer gills having a common 
membrane. Each gill is made up of two lamellas of radiating filaments. 
Pine markings cross the filaments at right angles, thus giving each 
lamella a delicate lace-like appearance. 

When a few grains of carmine powder are sprinkled on the gills the 
small grains pass to the base of the gills and then move toward the 
anterior end in a definite channel. This movement is due to the cilia 
between the filaments, which cause the grains to pass toward the mouth. 
The work of the gills is not only to strain out the food but to aid in 
resijii'ation. The impure blood flows into the capillary spaces of the 
gills, where the delicate membranes are bathed by the inflowing water, 
and, having acquired a new supply of oxygen, passes back to the heart. 
The area is increased by the folding of the lamella. If stimulated, the- 
gills contract immediately, shoAving that iliej joossess a nervous mech- 
anism. 

Palps. — Just dorsal to the gills on the borders of the mouth are 
two pairs of delicate filaments similar in structure to the gills. These 



OF MASSACHUSETTS. 17 

organs are the labial palps (Ip), which correspond to the lips of 
higher animals and function in conducting the food to the mouth. The 
central portion of these lips, which extend laterally for a distance equal 
to the thickness of the animal near the umbo, has arbor-vitas-like proc- 
esses, concealing the mouth. The flaps which extend on each side of 
the branching area are united to the body dorsally and posteriorly, 
leaving the other edges free. The exterior surface is smooth, while the 
internal surface is covered with ciliated ridges and furrows which aid 
in conducting the food from the gills to the mouth. 

Digestive System. — The digestive system of the scallop is compara- 
tively simple. The mouth opens into a short oesophagnis or gullet, which 
leads into a gourd-shaped stomach (s). On the posterior end of the 
stomach is a curious hard socket into which fits the tip of a translucent 
gelatinous rod, the crystalline style. This rod extends along the in- 
testine in a sort of pocket or groove as far as the lower part of the 
visceral mass (Fig. 75, vm). The stomach is enveloped by a dark-brown 
mass, connected with it by two short canals, one on each side. This 
large conspicuous organ is the digestive gland or "liver" (1), and "is 
only bounded in the region of the stomach by the sexual gland on its 
ventral surface." Kellogg (6). The liver (1) sends secretions into the 
stomach to aid digestion. The food is caught up as soon as it leaves the 
stomach by the eiHa of the intestine (i), which forms a double loop in 
the visceral mass (Fig. 76, vm). It then passes in a dorsal direction 
through the liver, curving posteriorly to pass through the heart, and 
finally ends posterior to the ventral portion of the adductor muscle. 

Circulatory System. — The scallop has a blood system passing over 
the whole body and through the gill filaments, where the blood is 
aerated. The heart (ht), a three-chambered organ, is situated in a 
pericardial cavity dorsal to the adductor muscle. The intestine passes 
through the pericardium and is surrounded by the ventricle of the 
heart. The auricles are two filmy bodies connected with the ventricle. 
From the heart arise the different arteries which conduct the blood to 
all parts of the body, whence it is returned through the venous system 
to the sinus venosus, from there to the gills, and finally back to the 
heart. 

Nervous System. — The nervous system of the scallop is complicated, 
and the animal is highly sensitive in all parts, especially in the region of 
the mantle, through the circumference of which passes a large nerve 
connecting with the tentacles and eyes. Several ganglia lie in the region 
of the mouth, foot and visceral mass. From these, numerous nerves 
pass to the various parts of the body. 

Excretory System. — The kidneys are a pair of yellow-colored organs 
in the form of sacs, encircling the anterior part of the adductor muscle. 
These glandular organs open into the mantle chamber above the gills, 
where thej are joined by the openings of the reproductive organs. 



18 THE SCALLOP FISHERY 

Foot. — The foot (f ) of the adult scallop is a small muscular organ 
extending from the upper part of the visceral mass dorsally for about 
a quarter of an inch. It is nearly cylindrical, with a deep groove on one 
side and a hollow, sucker-like disc on its distal end (Fig. 42). It has a 
slight twist which places the cleft portion in juxtaposition to the right 
valve, instead of on the ventral border. This is of use to the young in 
crawling, as the sucker can be put down evenly on the surface without 
a twist of the foot to hinder the retraction. Jackson (4). The func- 
tion of crawling is only for the young, and the adult has either lost the 
power of locomotion through degeneration or at least does not make 
use of it. A byssal gland (bg) is on the proximal end of the foot, and 
secretes the bundle of threads by which the moUusk anchors itself to 
various objects, as described under " Attachment " in chapter IV. 

The Reproductive Organs. — The generative organs comprise a large 
share of the soft parts of the scallop, and lie, surrounding the folds of 
the intestine, in the lower portion of the visceral mass. The surface of 
this mass, which terminates bluntly some distance below the large 
adductor muscle, is usually covered with a black glossy pigment, which 
is especially noticeable previous to and during the spawning season, 
when it completely hides the bright color of the egg sac. Both the male 
and the female organs are found in the same scallop, whereas in P. 
tenuicostatus, the giant scallop of the Maine coast, the sexes are sepa- 
rate. Drew (1). 

The testis (Fig. 75, ts) or male gland is a cream-colored organ lying 
just ventral to the liver and foot and extending down the side of an 
orange-colored sac. This sac is the ovary (ov) or female gland, which 
during the spawning season takes on a bright orange color, presumably ■ 
due to the number and ripeness of the eggs. In size it is somewhat 
larger than the testis, and lies ventral and slightly posterior to that 
organ. During the early part of the spawning season, when full of 
eggs and spermatozoa, these glands are well rounded and brilliantly 
hued; but after the completion of spawning they become small and 
lighter colored. In the ovary of the scallop previous to spawning are 
many millions of little eggs in various stages of maturity. These eggs, 
held in large follicles, are packed firmly in place, giving to the genera- 
tive mass a smooth, plump appearance. Dr. James L. Kellogg has 
kindly permitted the use of an illustration from his work on the " Mor- 
phology of Lamellibranchiate MoUusks, 1890," which shows a section of 
the generative organs of Fecten irradians, and supplements it with the 
following excellent description : — 

Pig. 67 represents a section passing vertically through the outer wall of 
the visceral mass, where the testis and ovary are closely apposed. The 
body wall is represented at ep and consists of a single layer of columnar, 
ciliated, epithelial cells, whose nuclei are about equally distant from their 
outer ends and the thick basement membrane (bm). In this epithelium are 



OF MASSACHUSETTS. 19 

many conspicuous gland cells (glc). Between it and the follicles of tlie 
generative gland is a thick layer of connective tissue, extending in between 
the follicles. The follicles of the ovary (ov) are not so regular in outline 
when seen in section as those of the testis (t). The walls of the latter 
bear a follicular epithelium (fep). In the ovary, the cells of this layer are 
in all stages of development into eggs. The eggs themselves, crowding 
the follicles, possess a very thick membrane and their protoplasm is finely 
granular. A duct from the follicles is seen at d. 

The mother cells of the spermatozoa (fep) are circular and of constant 
size in the follicles of the testis (t). As we follow the mass of cells inward 
from these mother cells they become very gradually smaller and smaller, 
until their final divisions result in the spermatozoa. They are so arranged 
that their " tails," in forming, project in extended masses toward the lumen 
of the follicle and give it a radiating appearance. I have not been able 
to determine how many times a mother cell divides in forming spermatozoa, 
for the cells are all rounded and give no evidence of their divisions, as 
they do in the testes of many animals. A duct of the testis containing 
spermatozoa is shown at d. The ducts of both testis and ovary are com- 
posed of slightly columnar, ciliated cells. In the wall of the duct of the 
testis is shown a single deeply stained cell, which is evidently a gland cell. 



CHAPTER III, — EARLY LIFE HISTORY. 

The Ripening of the Reproductive Organs. — In the early spring the 
sex products of the scallop begin to ripen, as the eggs and spermatozoa 
mature preparatory to the summer spavs^ning. The final ripening takes 
place during the month of May, Avhen the water has reached a tempera- 
ture ranging from 45° to 50° F., and the scallop is prepared "to shoot 
its spawn " in the first part of June. During the month of May the 
generative organs take on a plump appearance; the eggs grow larger; 
the spermatozoa become active; and the ovary passes from an indis- 
cernible pink to a deep orange color. This change in color furnishes 
a general index for recording, by the aid of color charts, the spawning 
period of the scallop. 

The Egg. — The egg or female cell (Fig. 1) is a small spherical body 
surrounded by a thin membrane inclosing a protoplasmic fluid. Lying 
in the protoplasm are numerous yolk granules which give to the egg an 
opaque appearance. These granules form the nutritive part of the egg. 
The shape of the mature egg when extruded appears spherical, but, 
when measured, one axis will be found slightly longer than the other. 
If the eggs are cut from the ovary they have a variety of shapes, due 
to the manner in which they were compressed within that organ (Fig. 
3). The scallop egg resembles that of the clam and oyster in size, the 
average diameter being about ^loo of an inch. In the ovary the eggs, 
when mature, have an orange color, and when discharged " en masse " 
still retain that color; but when separated appear to the naked eye as 
minute white specks. The color intensity of the mass seems to be due to 



20 THE SCALLOP FISHERY 

the arrangement of the yolk granules within the egg. A light color ap- 
pears to be caused by large vacuoles or clear spaces among the yolk 
granules, as are often found in distorted and immature eggs. Evidently 
the number, size and arrangement of these vacuoles in respect to the 
granules determine the color of the mass, and thus indicate the maturity 
or immaturity of the eggs. Orange-colored ovaries when placed in 75 
per cent, alcohol in a short time become Avhite, the orange color being 
extracted by the fluid. 

The Spermatozoon. — The spermatozoon or male cell (Fig. 2) is 
extremely minute, being only an exceedingly small fraction of the size 
of the egg. It consists fundamentally of two parts, an elliptical head 
and a slender whip-like tail, which is used as an organ of locomotion 
in seeking the egg. The size of the head is V2Q0 by %oo of a millimeter 
(%500 by H2500 of an inch), with a tail about %o of a millimeter 
(%oo of an inch) in length. The minute anatomy was not studied. 

Spawning. — The term " spawning " refers to the discharge of the 
eggs from the female or the spermatozoa from the male. With most of 
the lamellibranchiate moUusks, the class to which the scallop belongs, 
it is the act of throwing off the sex products, which meet in the water for 
the purpose of fertilization. Pecten irrudians, as is often the case with 
highly specialized mollusks, is hermaphroditic, i.e,., both sex elements are 
found in the same individual. Spawning in this instance is the dis- 
charge of either eggs or spermatozoa from the same animal, usually 
at different times. 

In the Pectinidae the opening from both ovary and testis lead into a 
common duct with a single orifice, which opens into the kidney com- 
paratively near its external aperture. Pelseneer (9). The sexual 
products, as they are extruded, pass through a part of the kidneys just 
dorsal to the large adductor muscle into the mantle chamber, where 
they are discharged into the water. The discharge takes place through 
the pseudo-siphon, formed by the mantle when closed, at the right or 
posterior edge of the shell,, as the animal lies in a natural position. 
The spawn is usually cast forth as a fine spray by a quick snap of the 
valves and is rapidly diffused through the water, though sometimes the 
valves remain quiet, the spawn then passing out in a steady stream. 
As the mantle fringe is slightly ojjened to allow the spawn to roll gently 
out, this latter method can be compared to the exhaling of tobacco smoke 
from the human lips. If eggs are given off they either appear in pink 
masses or are just visible to the naked eye as fine white specks, making 
it possible for the observer to readily distinguish them from the sperma- 
tozoa, which give to the water a quivering, milky appearance. The 
amount of eggs extruded at one time varies considerably, but generally 
numbers high in the thousands and even millions. 

The following observations upon Ihe spawning of individual scallops 
were made at Monomoy Point. The scallops were confined, as described 



OF MASSACHUSETTS. 21 

in chapter VII., in small aquaria during the period of observation, and 
were replaced in their native element between times. Possible error 
arises from the unnatural conditions, which may render the spawning 
abnormal. Unfortunately no satisfactory method of eliminating this 
error could be devised. These observations, however, have been par- 
tially confirmed in other ways. 

(1) When the scallop spawns, ichich sex cell is liberated first? 
Observations on 38 scallops showed that 19 produced spermatozoa, 

17 eggs, and 2 a mixture of both at the first discharge. In general, the 
scallop continues shooting for a number of discharges the kind of sex 
cell with which it starts, and although scallops are hermaphroditic, only 
a single kind is usually given off at any one time, the length of the 
period varying from a few minutes to five or six hours. It can be safely 
concluded that it is purely a matter of chance which sex cell is given 
off, and that the tendency toward one kind may be a precaution against 
self-fertilization. 

(2) How long are the intervals between discharges? 

The intervals between discharges vary from one-half a minute to 
forty-five minutes, or even days. After a series of rapid discharges the 
resting period appears to be longer. One scallop was observed to give 
as many as five successive discharges, while two are of frequent occur- 
rence. Other specimens have been observed to shoot spawn at intervals 
of two or three minutes for over five hours. The scallop possibly can 
adapt itself to existing conditions and spawn only at favorable times. 
If the germ cells are set free at intervening periods over a long space of 
time there is a gTeater chance of surviving, 

(5) Do scallops throw all their spawn in one day? 

Numbered scallops were placed in separate aquaria for periods of 
two hours for several days, a record being kept of the spawning of 
each individual. After each test the animals were suspended in wire 
baskets from a raft at a depth of 10 feet in water, which was consider- 
ably cooler than the sun-warmed water in the aquaria, probably pre- 
venting further shooting of spawn. Although only 25 per cent, threw 
spawn we can infer that scallops shoot their sex products little by little, 
as the same individuals were found to give forth spawn after an interval 
of several days. This fact indicates that the spawning season for one 
scallop probably extends over a period of days and even weeks. Rec- 
ords with color charts, upon scallops of another set, likewise show 
that spawning is gradual, 

(4) Do scallops spawn at any particular time of day? 

Scallops have been observed to spawn as early as 8.15 a,m, (July 13, 
1907) and as late as 4,30 p.m. (July 12, 1909), and at various times 
between these hours. Although sunlight is more favorable, the scallop 
will spawn on cloudy days and probably at night, as the time of spawn- 
ing is largely determined by the temperature. 



22 THE SCALLOP FISHERY 

(5) What temperature is most favorable for spawning? 

In confinement scallops have been observed to throw spawn at all 
temperatures from 68° to 84° ¥., although above 76° F. was most 
favorable. Great variation is found, as every scallop is a distinct 
individual and the eggs vary in degree of maturity. One scallop gave 
off its sex elements at a temperature of 68° F. in fifteen minutes after 
being placed in the aquarium, while at 78° F. one spawned in three 
minutes and others took hours. Under natural conditions the spawning 
season begins when the water reaches 61^ °F. As a rule high tempera- 
tures are most condiicive for spawning. 

(6) At what age does a scallop first spawn? 

The extreme rapidity of growth makes it possible for the scallop to 
spawn when exactly one year old. With the clam, spawning occasionally 
occurs at the age of one year, with the quahaug only in very exceptional 
eases, but with the scallop the most important reproductive period, and 
the only one of practical value, comes at this early age. This fact is 
explained by the short life of the scallop, from twenty to twenty-six 
months, as compared with the many years of the clam and quahaug. 

(7) 7s there a second spawning season? 

For the majority of scallops there is only one spawning season. Na- 
ture has so regulated that less than 25 per cent, attain a length of life 
of two years. In the few scallops which pass the two-year mark, eggs 
and spermatozoa apparently develop normally, and if the animal lives 
through the season it produces offspring for the second time in its life. 
These two-year-old scallops are larger, and the ovaries and testes are of 
correspondingly gTeater size. Two-year-old scallops are occasionally 
found in small beds, but large numbers are by no means of common 
occurrence. In the protected Avaters of the Powder Hole two-year-old 
specimens were frequently found. During the summer of 1909 a com- 
paratively large number of the set of 1907 were found. This set was 
peculiar for its slow growth and small size, the two-year-old animals 
being about the size of normal one-year-old scallops. The spawning 
of this set was perfectly normal during the second season, and the sex 
products could in no way be distinguished from those of yearlings. 
Although it is possible for scallops to spawn a second time, provided 
they pass the two-year limit, their economic impoi:tance is slight, owing 
to the small per cent, which survive so long. The first spawning season 
must, therefore, be considered the only practical one in legislation for 
the welfare of the scallop fishery. 

This fact proves that all scallops under one year old must he pro- 
tected, as these furnish practically all the spawn for the following 
year. Only scallops under this age need protection. If the scallop 
under this age is amply protected, the law has done all in its power to 
insure the future of this profitable industry. It does no harm to captui'e 
scallops over one year old; in fact, it would result in economic loss if 



OF MASSACHUSETTS. 23 

they were not taken, as nearly all die from natural causes before a 
second season. 

The Spmvning Season. — In Massachusetts waters, owing to the 
diversity of conditions as regards locality, environment and seasonal 
changes, it is difSeult to define the spawning season exactly and only 
general limits can be given when the entire territory is considered. As 
a rule, temperature seems to be the controlling factor, as is demon- 
strated by the variation of the season according to locality and years. 
The entire period roughly covers two months, averaging from the middle 
of June to the middle of August (Fig. 83). The height of the spawning 
occurs during the first weeks in July, and although the season drags on 
for a month longer, the greater part of the mature eggs have been liber- 
ated. Different localities, with the same general limits, often vary in 
having the height of the spawning at different times. While the spawn- 
ing of the scallop as a class extends for two months, the duration of the 
season for the individual runs anywhere from one day to several weeks, 
(a) Spawning Season at Monomoy Point. — During the summers of 
1906 and 1907 the spawning season of the scallop was followed in the 
waters of the Powder Hole at Monomoy Point, and supplementary 
observations were made during 3908 and 1909. During the first two 
years conditions in this locality were practically the same, thus eliminat- 
ing nearly all variation factors except seasonal change. It is, there- 
fore, fair to assume that the following variations are mostly due to 
the difference in the temperature of the two years. 

In comparing the two years 1906 and 1907 the following points will 
be considered: (1) date of first spawning; (2) length of time spawn 
could be obtained for successful artificial fertilization; (3) date of 
appearance of the set on raft spat collectors. 

(1) Careful observations were made in regard to the beginning of 
the spawning season, and the start was accurately determined for this 
locality. In 1906 scallops first extruded eggs and spermatozoa on 
June 12, and in 1907 on June 21, a variation of nine days. The average 
temperature of the water on June 12, 1906, was 61.5° F., on June 21, 
1907, 61.5° F. June 4, 1906, was equivalent to June 18, 1907, in 
regard to the temperature, which reached 60° for the first time on these 
dates, showing that the seasonal variation in temperature was about 
two weeks. In both cases there had been a previous rise in temperature. 
By June 20 this difference had vanished and the daily temperatures for 
the two years were approximately the same (Fig. 81). 

(2) For successful artificial fertilization spawn could be obtained 
for both years as late as July 20. Mature eggs and active spermatozoa 
were found in the reproductive organs later, but the scallops did not 
give forth spawn readily after this date. The records made with the 
color chart show that the spawning season is not complete before the 
middle of August. 



24 THE SCALLOP FISHERY 

(3) Very little variation was found in the sets of 1906 and 1907 
on the raft spat collectors, but the 1908 and 1909 sets were slightly 
earlier, though fewer in number. The temperature of the water at the 
time of set was about 70° F. In 1906 the set began July 26 and reached 
its height August 4 ; in 1907, July 24 and August 2 ; in 1908, July 18 
and July 26; in 1909, July 22 and July 29, respectively. 

In the above cases, more especially the first, temperature seems to be 
the controlling factor. The warmth of the water determines an early 
or late spawning season, as is shown by the difference in the start of the 
seasons of 1906 and 1907, the latter being nine days behind the former. 
In each ease spawning did not start until the water had assumed a tem- 
perature of 61.5° and had been over 60° for a few days. Spawning 
does not take place until the temperature of the water is sufficiently high 
to enable the young larvae to live. Thus, in comparing the two years 
we find that the variation in the spawning compares in every detail 
with the variations in temperature, and, when other factors are elimi- 
nated, depends directly upon it. The average summer temperature 
controls the length and completeness of the spawning season, as is 
directly manifested by the time and amount of set. 

(&) Conditions influencing the Spawning Season. — In any given 
area the spawning depends on the latitude and on the climate, tempera- 
ture again being an important factor. In Rhode Island, in the warmer 
waters of Narragansett Bay, the season lasts from June 1 to July 1, 
reaching its height about June 15, Risser (2), as compared with 
June 15 to August 15 in Massachusetts waters. Naturally the farther 
south the earlier the season, as the warmer waters hasten the spawning. 

While the temperature is the main factor in determining the spawn- 
ing, it is by no means the only one. The natural conditions of any local- 
ity, such as its suitability for growth, for food, depth of water, kind of 
bottom, enemies, exposure, and other factors which make up the environ- 
ment of the scallop, play their part in detennining the spawning 
season. Scallops in shallow water spawn slightly earlier than those in 
the deep, probably due to difference in temperature, while those under 
favorable growing conditions probably spawn in advance of scallops 
less favorably situated. 

(c) Length of Season in Massachusetts Waters. — The different local- 
ities present considerable variation not only within their borders but 
with each other. The four sections of the scalloping territory given in 
chapter VI. are useful for a comparison of the spawning season, owing 
to their divergent conditions. The work of determining the spawning 
season, as described in chapter VII., was conducted during 1905 and 
1906 by (a) general obsei'vations of the ovary; (b) color chart records; 
(c) appearance of set. 

(1) On the north side of Cape Cod conditions are not favorable for 
scallops and there is but a small industry. In Cape Cod Bay the water 



OF MASSACHUSETTS. 25 

is colder than south of the Cape, and the spawning would naturally be 
somewhat later. In the harbors, such as Wellfleet Bay, the reverse is 
true, as the broad exposure of flats, heated by the sun, gives a greater 
warmth to the water. In these eases many scallops are left in little 
tide pools, where they bask in the sun and shoot spawn in these small 
natural aquaria. The eggs have thus a chance to develop in quietude 
until the incoming of the tide, when the little embryos join comj)any 
with the young from the other pools and begin the keen competition of 
life. The spawning season lasts from June 25 to AugTist 15. 

(2) On the south side of Cape Cod is found a great variety of terri- 
tory and conditions, which nearly approximate those of Monomoy 
Point. The limits of the season in this locality are from June 15 to 
August 15. 

(3) The conditions at Nantucket and Edgartown closely approximate 
those on the south side of Cape Cod, and except for local variations the 
spawning season is the same. 

(4) In the warmer waters of Buzzard's Bay spawning is somewhat 
earlier, the set usually being about two weeks in advance of Monomoy. 
The limits of the season scarcely differ from the south side of Cape Cod 
and the Islands, but the main part of the spawning takes place earlier. 
The season lasts from June 1 to August 1. The Buzzard's Bay scallop 
is larger in size than the scallop in the other localities, owing to earlier 
spawning and rapid growth. 

Fecundation. — Fecundation is the union of the female cell (egg) 
with the male cell (spermatozoon), which results in the formation of a 
new individual that partakes of the nature of both parents. Since the 
eggs of the scallop are fertilized externally, in the water, it is com- 
paratively easy to watch the act of fertilization and the subsequent 
development of the embryos. In the water a transparent substance 
envelops the egg, which holds the spermatozoa a short distance from 
the cell proper (Fig. 6). The only reason for believing that such a 
substance is present is the fact that preserved eggs still retain the 
circle of spermatozoa. The attraction of the male cell to the egg is 
believed by scientists to be of chemical origin. Although the egg is 
thickly surrounded with spermatozoa, only one is needed for fertiliza- 
tion, and after its entrance the rest are held outside by the formation 
of a membrane through which they cannot penetrate. Occasionally 
more than one spermatozoon enters the egg, but in this case the egg 
possibly fails to attain complete development. 

(a) Natural Fecundation. — Judging from the enormous number of 
eggs and spermatozoa annually liberated by a single adult scallop, 
nature seems prodigal with her bounties; but on second thought it 
appears that an equilibrium has been established and that an abundance 
of spawn is needed to compensate for the destructive agencies which 
beset the scallop. It seems strange, perhaps, that the spermatozoa 



26 THE SCALLOP FISHERY 

should outnumber the eggs 1,600 to 1, as it only requires one sperma- 
tozoon to fertilize one egg. But as the small male cell has the active 
part of finding the egg, this again is a wise provision of nature, whereby 
this proportion vastly increases the chances of natural fecundation. 

If only 1 scallop arrives at maturity from 3,000,000 eggs, it is suffi- 
cient, under normal conditions, to perpetuate the species. Naturally 
there is a vast destruction of eggs and young scallops, an important 
part of which is due to the loss of eggs through non-fecundation, i.e., 
the eggs and spermatozoa not meeting in the water. There are a great 
many chances in nature against fertilization of the egg. Scallops may 
be some distance apart and the spermatozoa must travel far before 
they can meet the egg. Water currents, winds and other weather con- 
ditions may prevent this union. Fertilization is partly by chance, as 
the male cell can only be attracted to the egg from a short distance. 
Thus, if it were not for the abundant supply of sex products the race 
of scallops would soon be exterminated. 

In artificial fertilization a large number of the eggs are not fertilized, 
and, failing to develop, soon decompose and pollute the water, thus 
causing the death of the more advanced larvse. This shows that per- 
haps all the eggs given forth at one time from the scallop are not 
ready for fertilization and cannot develop, and it may be supposed 
that, under natural conditions, an indeterminable per cent, of the ex- 
truded eggs are incapable of development. 

(&) Self -fecundation. — Pecten irradians is hermaphroditic, i.e., both 
sex elements are found in the same individual. Pelseneer (9) asserts 
that : " In hermaphrodite mollusks the spermatozoa ripen before the ova ; 
the hermaphroditism is therefore protandrie. The hermaphroditism 
also is not self-sufficient, and the ova of one individual must normally 
be fertilized by the spermatozoa of another individual." Pecten ir- 
radians is an exception to this in that both the eggs and spermatozoa 
mature at the same time, and that self-fertilization frequently occurs 
although it is not the common method of reproduction. 

In nature it is not usual for scallops to produce both male and female 
cells at the identical moment, and self-fertilization is therefore not 
as common an occurrence as when scallops are confined in aquaria. 
Scallops often shoot eggs and spermatozoa within as short an interval 
as 15 to 30 minutes apart. In numerous cases self-fertilization has 
been observed during the spawning experiments. The spermatozoa 
and eggs of the same scallop have been artificially mixed, and the early 
embryological stages followed. Whether these self-fertihzed eggs 
would develop into mature scallops was not determined, as the devel- 
opment was only followed as far as the troehosphere larva, up to 
which period it was normal. Drew (1) and Risser (2) also have made 
observations on the self -fertilizing powers of the individual Pecten irra- 
dians. 

Fertilization of the Eggs of Two-year-old Scallops. — In spite of 



OF MASSACHUSETTS. 27 

the fact that the second spawning of the scallop occurs during its old 
age, and that the majority of this species do not reach a second season, 
the eggs of two-year-old scallops may be fertilized and pass through the 
normal cleavage stages. Although there were some indications that 
the subsequent development under artificial conditions is not as satis- 
factory as that of the younger scallops, there is no proof that their 
development under natural conditions is anything but normal, or that 
they cannot produce hardy offspring. Naturally, as the two-year-old 
scallops are few in number their offspring are not numerous. Under 
artificial conditions as compared with the younger scallops they do 
not seem to produce spawn so readily and fewer larvae in proportion 
are raised to the early swimming stage. These observations cannot 
be considered as conclusive, as the special Powder Hole set of 1907, 
already referred to, during 1909 furnished as healthy spawn as the 
1908 set. 

Embryonic Development. 

The early life of Pecten irradians can be separated arbitrarily into 
two main divisions, (1) the embryonic or sub-veliger life, which com- 
prises the development of the animal until it acquires a shell; and (2) 
the post-embryonic life of the young scallop before it attains adult 
characteristics. 

The post-embryonic life is further subdivided into the (a) early 
veliger stage, when the animal is a free swimming larva with a straight 
hinge line (Fig. 17); (&) late veliger or prodissoconeh stage, distin- 
guished by the curved hinge and development of gills and foot 
(Fig. 18) ; (c) the dissoconch stage, where notable changes occur as a 
result of the "setting," that is, adjustment by spun byssus threads; 
(d) plicated stage, where the ridges and the furrows characteristic of 
the adult shell appear. 

The embryonic development of Pecten irradians is in many respects 
so similar to that of its large relative, Pecten tenuicostatus Mighels, the 
giant scallop, so ably described by Dr. Gilman A. Drew (1) that it is 
difficult to present a complete account without a repetition of many 
interesting facts. For this reason special emphasis has been placed on 
the points of difference between the two species, and only general con- 
sideration given those of common interest. In reporting upon this 
phase of the life history of Pecten irradians, it is perhaps worthy of 
mention that the results here embodied, imperfect as they are, have 
been obtained from hundreds of scallops under different conditions and 
from four years of successive observations. 

The Development of the Egg. 
The development of the egg after fertilization is by the usual process 
of cell division, whereby the single ovum is transformed into a living 
mass of tiny cells. Like most lamellibranehs, in which fertilization 



28 THE SCALLOP FISHERY 

takes place externally to the parent, the scallop develops by the normal 
process of unequal cell division, and its subsequent growth as far as 
the prodissoconch stage is similar in nearly every respect to the devel- 
opment of the clam, oyster and quahaug. 

The Polar Cells {Figs. 4, 5). — The first noticeable change in the 
external appearance of the egg occurs about thirty-three minutes after 
it is laid. At one part of the egg, Avhich from this time forth becomes 
the so-called animal pole or region of the greatest activity, appears a 
small translucent globule, Via the diameter of the egg. This is known 
as the first polar cell, and is soon followed by a second body of similar 
nature, which pushes out behind the first in such a manner as to 
separate it from the egg. Both adhere to the egg by protoplasmic 
strands, such as described by Drew (1). With Venus mercenaria (the 
quahaug or hard-shell clam) the polar cells form beneath a thin mem- 
brane, and are held to the egg by strands from this source. Such a 
covering is not well marked in the scallop egg, which appears naked, 
and the protoplasmic strands may possibly have a different origin. 
The polar cells contain no yolk granules, as is shown by their trans- 
parent appearaliee. They remain with the egg through all the varied 
stages of cell division, and can be seen still adhering to the first ciliated 
larv£e, evidently disappearing during the early swimming stage. 

The Yolk Lobe. — About ten minutes after the first polar cell is 
formed, the opposite side of the egg, now known as the vegetative pole, 
elongates, giving to the egg a pear-shaped appearance. The constric- 
tion at the small end is the so-called yolk lobe (Fig. 5) which forms a 
few minutes previous to cleavage. Pecten irradians differs somewhat 
from Pecten tenuicostatus in regard to the time of formation of the 
yolk lobe. In the case of the latter species. Drew (1) has shown that 
the yolk lobe appears previous to the polar bodies, and that it becomes 
prominent when the second polar body is formed, only to disap- 
pear and again to become prominent when the egg cleaves into 
two cells. The yolk lobe in the forrner was not seen until after the 
formation of the polar cells, and not until just before the first cleavage 
did it become markedly prominent. It forms in about three minutes, 
and is completed one minute before the first cleavage takes place. 

The First Cleavage. — Soon after the formation of the yolk lobe and 
the differentiation of the egg into the animal and vegetative poles a 
constriction takes place parallel to the longitudinal axis of the egg, 
dividing the broad end into two unequal cells, the smaller one-half the 
size of the larger, with the polar bodies between them (Fig. 7). The 
actual time consumed from the beginning to the completion of the first 
cleavage varies from two to twelve minutes, but usually it takes about 
three minutes to effect the change. This first division occurs forty-six 
minutes after the egg is fertilized. 

The action of the yolk lobe during this division is somewhat peculiar. 



OF MASSACHUSETTS. 29 

Previous to the first cleavage tlie egg has taken on a pear-shaped appear- 
ance, due to the formation of the yolk lobe. During cleavage this lobe 
in many of the eggs became so constricted that the dividing egg had a 
three-celled appearance. Then it gradually disappeared, in one ease in 
the course of seven minutes, leaving only a large and small cell. The 
form of the different eggs during cleavage varies greatly, some dividing 
with scarcely the appearance of a yolk lobe, others with prominent con- 
strictions. 

The next cleavage (Fig. 8) divides the egg into four cells in a vertical 
direction, and passes through the animal pole nearly at right angles to 
the first cleavage plane, and a little to one side of the center. This 
di\nsion forms three small cells and one large, the latter holding the 
nutritive or yolk part of the egg, originally contained in the region of 
the yolk lobe. The second cleavage occurs from fifty-five to eighty-one 
minutes after fertilization, the average time being sixty-seven minutes. 

The third division (Fig. 9) is in a horizontal plane, dividing the four 
cells into eight. The four upper cells, which lie next to the polar bodies, 
are much smaller than the lower ones, and from this time forth are 
designated as the mieromeres, while the large lower cells are known as 
the maeromeres. During the process of cleavage the upper layer of cells 
twists 45°, so that they alternate with, the lower cells, furnishing an 
excellent illustration of the spiral cleavage so common in nature. The 
time of arrival at the eight-celled stage varies from fifty-eight to one 
hundred and ten minutes after fertilization, the average being about 
eighty-one. 

From this time on the mieromeres divide rapidly into smaller and 
smaller cells, during which the egg passes successively through sixteen, 
thirty-two, sixty-four, etc., celled stages, finally forming a layer around 
the maeromeres. The average time of the sixteen-celled stage (Fig. 10) 
is about one hundred minutes after fertilization. Cell division continues 
until the single primitive ovum has become a compact mass of small cells 
surrounding four large cells, the maeromeres, resulting in a type of the 
epibolie gastrula, which later becomes a true invagination by the further 
division of the maeromeres. From a surface view the animal is merely 
a rounded mass of cells, still bearing the two small polar bodies (Fig. 
11.) Soon the inner layer of cells forms an infolded cavity, the areh- 
enteron or primitive digestive tract, which opens to the exterior. The 
mieromeres now make up the ectodermal, the maeromeres the endo- 
dermal layer. 

By this time the surface cells have developed cilia, and the animal 
acquires the power of locomotion (Figs. 12 and 13). It is important 
that the scallop become active at this period of its existence, as other- 
wise it would perish. In the laboratory the majority of the eggs settle 
to the bottom of the glass dishes until this stage is reached. Doubtless 
in nature the egg, unless held in floating masses or kept in suspension 



30 THE SCALLOP FISHERY 

by the currents, falls to the bottom, where it remains until it acquires 
cilia. The majority probably perish before they reach the swimming 
stage, either through not being fertili^ied or because of settling on un- 
favorable bottom. 

The swimming period is reached from nine to twelve hours after 
fertilization, ten hours being the usual time. Little change has taken 
place in the size of the animal, and the entire scallop is hardly larger 
than the original egg. Development is rapid during the swimming 
period, not so much in size as in change of form from the early swim- 
ming gastrula to the trochosiDhere larva. There are three phases of 
development in changing from the early gastrula to the advanced 
troehosphere. (1) The animal is a mere rounded mass of cells covered 
with cilia. (2) The body has elongated, the blastopore or primitive 
mouth becomes more noticeable, and the cilia instead of being general 
are confined to a special portion of the body, which later proves to be 
anterior end (Fig. 14). In the course of two hours after phase 1, the 
cilia on the frontal cell at the anterior end of the body elongate until 
they attain seven -ninths the length of the body (ordinary cilia measure 
one-fifth the length of the body), and unite to form a bundle called the 
flagellum, which guides the swimming embryo. Ordinarily it has the 
appearance of a single last or whip, so closely are its parts united, but 
as many as six individual cilia have been counted in this bundle. The 
anterior end of the animal has in the mean time become larger and 
heavier, while the posterior half has elongated, giving the scallop a top- 
shaped appearance. (3) The third phase is marked by another invag- 
ination on the dorsal side of the animal, directly opposite the blastopore. 
This is the primitive shell gland which secretes the shell. Pelseneer (9) 
in considering lamellibranchiate mollusks as a class says of the shell 
gland : " During its extension it gives rise to a saddle-shaped cuticular 
pellicle, which becomes calcified at two symmetrical points, right and left 
of the middle line. These two centers of calcification eventually form 
the two valves of the shell. . ." 

The transition from the early swimming gastrula to the advanced 
troehosphere is well illustrated by the development of the swimming 
powers of the young scallop. As soon as the embryo has acquired cilia 
it starts with a rolling motion, at first slowly, but later faster as it 
increases in strength, turning over and over on the bottom of the dish. 
This simple method of changing position is by a rotation on the longi- 
tudinal axis which might be compared to the movement of a top before 
it totters over. The embryo rotates in one place or hutches along in 
random directions. The rate of this action varies greatly, anywhere 
from five to twenty turns being counted in ten seconds. The cilia soon 
perform the functions of swimming organs, and the little animals rise 
through the water towards the surface, where they can get a better 
supply of oxygen. The first swimming movement is a compound motion 



OF MASSACHUSETTS. 31 

consisting of simple rotations plus revolutions. The prevailing revo- 
lution is clockwise, but the motion is intermittent and the direction can 
be changed at will. With the development of the flagellum, a definite 
direction of motion arises. The animal nearly always swims with the 
flagellum anterior, although one case has been observed where the animal 
swam in a reverse direction for a short distance. Possibly the flagellum 
serves to increase the speed, which becomes so rapid that it is difficult 
to follow the animal with a microscope of 41 magnification. The motion 
is now efHeeted in a straight line by spiral revelations along the longi- 
tudinal axis of the animal. This final motion is probably the culmina- 
tion of the previous aimless rotations. 

The Shell Gland. — The formation of the shell gland, which occurs 
twelve to fourteen hours after fertilization, marks a decided change in 
the character of the young scallop (Fig. 15). In the course of a few 
hours a thin transparent shell grows slowly over the animal, until it 
completely envelops the soft parts. At first the shell is so small that it 
scarcely covers the whole of the animal, which can be seen swimming 
through the water partly covered by the two thin valves. This shell is 
formed by the secretion from the shell gland, which becomes calcified 
at two points, forming the two valves. The hinge line at this early 
stage is flat and straight. At the same time, with the spreading of the 
shell, various changes of more or less importance, both in the anatomy 
and in the habits of the young scallop, have taken place, giving rise to a 
period in its development known as the veliger stage, perhaps the most 
critical and important period of its existence. 

The Veliger Stage. 

When reared in the laboratory the embryos reached the full veliger 
(shell) stage between seventeen and forty hours after fertilization, 
according to the temperature. Presumably the same time is true in 
nature, although the rapidity of development varies with the external 
conditions. The length of the veliger stage is likewise dependent on 
temperature and environment, the usual duration being about five to six 
days. During this period numerous changes of more or less importance 
take place, and the late veliger is an essentially different animal from 
the early form. It will be necessary, therefore, in describing the veliger 
stage, with all its involved changes, to arbitrarily divide it into two 
phases, the early (Pigs. 16 and 17) and the late veliger (Pig. 18) ; and 
in describing the anatomical changes it will be more satisfactory, after 
a brief survey of the essential features of each phase, to trace the 
development of the individual organs separately. 

The chief characteristics of the early veliger (Pigs. 16 and 17) are: 
(1) an equivalvular shell slightly inequilateral, without definite struc- 
ture, with a straight hinge line, no umbones being present; (2) a velum 
or ciliated swimming organ; (3) a primitive mouth lined with cilia, 



32 THE SCALLOP FISHERY 

leading into a cavity in the center of the body, the stomach, and an 
abbreviated intestine with a posterior anal opening; (4) an inconspicu- 
ous mantle; (5) anterior adductor muscle alone present; (6) size .093 
millimeter. The increase in size from the trochosphere stage is due to 
the formation (Fig. 16) of a cavity between the body and the shell. 

The late veliger is characterized by: (1) a shell of the same structure, 
marked by prominent umbones directed posteriorly; (2) a well-devel- 
oped foot which has succeeded a degenerated velum as the swimming 
organ; (3) a more complex digestive tract, with palps, and a coiled 
intestine; (4) a cons^Dicuous mantle; (5) a posterior adductor muscle, 
and the appearance of several gill bars; (6) size, .18 millimeter. 

In studying the life history of nearly every large lamellibranch which 
begins its life external to the parent, there is a gap between the ana- 
tomical changes of the early and late veliger periods, as it is a difficult 
stage to procure specimens for studj''. It is only possible in this history 
of the scallop to give the changes in the different organs by comparing 
the early and late vehgers, as we have not been able to identify with 
certainty the intermediate forms on account of the large number of 
species which so closely resemble each other, as they are collected in 
the plankton net at the surface. 

The Shell. — The veliger shell of the Peleeypoda or lamellibranehiate 
mollusks has been aptly given the name prodissoconeh by Jackson (4) 
to distinguish it from the succeeding shell, the dissoconch. With the 
scallop, I have taken the liberty to apply this term, which properly 
includes all of the veliger stage, to merely the late veliger, at which time 
it has acquired a form markedly characteristic of the scallop. Here- 
after, when speaking of the prodissoconeh shell, it refers only to the 
form of shell typical of the late veliger, as it remains differentiated 
from the succeeding dissoconch stage. In the early veliger, the shell 
consists of two valves of homogeneous structure joined dorsally by a 
ligament in a slightly concave hinge-line. 

The change from the flat hinge veliger (Fig. 17) to the completed 
prodissoconeh (Fig. 18), which marks the end of the veliger stage, is 
quite pronounced. The straight hinge line has given way to one of 
slight curvature, while the valves by their growth have formed promi- 
nent umbones, hiding the hinge line from lateral view. The umbones 
point posteriorly, but are less prominent than in the case of the oyster. 
The left valve is more convex than the right, and the right umbo is less 
prominent than the left (Fig. 19). In the completed prodissoconeh and 
probably in the early veliger ten pairs of teeth can be seen along the 
hinge line, five on each side of a central slit (Fig. 22). The question of 
teeth has always been of interest in the classification of lamellibranchs. 
These are later either obscured or absorbed by the growth of the shell. 
The teeth of one valve fit into the depressions of the other, adding 
strength to the hinge. The shell remains homogeneous, except for fine 
lines of growth parallel to the free edge. Its calcareous composition is 



OF MASSACHUSETTS. 33 

shown by effervescence when tested with acid. The scallop differs from 
Anomia glabra at this stage by having no byssal notch in the shell. 

The Velum. — The veliger derives its name from the larval swimming 
organ or velum peculiar to this period of its life. This organ, situated 
in the anterior part of the shell, consists of an elliptical pad, .046 milli- 
meter in length, with a border of short vibrating cilia, and supporting 
in its center a long flagellum. It is capable of extension and contraction, 
whereby it can be thrust out of the shell or drawn in quickly by means 
of retractor fibers, which are fastened to the shell near the posterior 
part of the hinge, so as to give a direct backward pull. Two fibers 
go to the ends of the velum, the third to the center. When contracted, 
the velum folds in to the form of a bell, the round ciliated edges curving 
toward the central part, which bears the flagellum. When expanded, 
the velum opens like the unfolding of a flower, the ciliated edges curling 
outward. When the velum is extended outside the shell, as the animal 
swims, the whole mass shifts ventrally, leaving a clear space between 
the hinge and the body. The flagellum serves during this period as a 
sensitory organ or feeler. The velum is of great use in swi mmi ng, 
and can rapidly propel the young scallop through the water by the 
lashing of its cilia in a manner similar to the action of oars in a 
boat. 

The development of the velum can be traced from the ciliated region 
of the early gastrula, and the organ is a direct modification of the 
anterior ciliated area of the trochosphere larva. The frontal cilia, 
with the long central flagellum, have become more centralized and 
stronger, while the ciliated arc has formed a muscular pad capable of 
extension and contraction. The flagellum and cilia of the veliger stage 
are identical with those of the trochosphere, the only change being a 
modification of the supporting area. 

While the transition from the veliger to the footed larva has never 
been completely observed in the scallop, it is doubtless identical with 
that of the clam, which is here described. This change takes place by 
the atrophy or degeneration of the velum and the simultaneous develop- 
ment of the foot. Several stages can be observed during this transition 
period : (1) the primitive veliger, with no foot or at best a rudimentary 
projection posterior to the mouth; (2) a reduced velum and a half- 
formed foot; (3) a small velum and a nearly complete foot; (4) no 
velum and a perfectly developed foot. During this period the mouth 
has advanced anteriorly and dorsally, following the disappearing velum, 
which vanishes in the region of the palps. 

Habits Swimming in the earlier veliger stage is wholly by the 

velum, while later this organ is assisted by the foot. The very young 
veliger is less active than the older larva, and is usually found at 
the bottom of the dish with valves widely open and velum partly pro- 
truded. In this case, the movement merely consisted of turning in a 
circle, as the velum was not thrust out far enough to enable the animal 



34 THE SCALLOP FISHERY 

to swim rapidly in a straight course. Only when the velum can be 
completely extended does the larva attain full swimming powers. 

When the velum is fully developed the animals become rapid swim- 
mers, and can be found in great numbers through the water, more 
especially near the surface, where they can be taken in a net of silk 
bolting cloth. When placed in a glass aquarium, if left undisturbed, 
they can be seen by the naked eye as white specks as they swim through 
the water. If the dish is subject to any sudden jar, such as a sharp 
tap with a pencil, the young scallop quickly pulls in the velum and 
settles to the bottom with closed shell. After a brief interval the ani- 
mal extends the veliun with a hesitating jerky movement, until it is 
fully expanded, and then resumes swimming. The usual direction is 
with the velum ahead, the cilia on the edges lashing with a rowing 
motion which propels the animal in the same manner as a boat is 
propelled by a man seated in the bow. There is also a turning motion, 
which whirls the larva anterio-posteriorly in either a clockwise or anti- 
clockwise direction. 

The Foot. — ^As the animal passes into the late veliger stage the 
swimming powers of the velum degenerate, while the foot with its 
ciliated tip becomes the only organ of locomotion. The footed larvae 
swim by a kicking movement of the foot. It is natural to suppose that 
there is a transitory stage where both the velum and the foot are used. 
The foot, the most useful organ of the young scallop, makes its appear- 
ance in the prodissoconeh stage, and for a long time serves as means 
of locomotion for the animal. It is a long, flexible organ, made up of 
both longitudinal and circular muscles, and entirely covered with fine 
cilia. On its tip or distal end are long cilia, comparable to the little 
tuft or cluster posterior to the mouth in the early veliger. The tong 
cilia are at first useful in swimming, but as the animal becomes larger 
they become relatively less important. The tip of the foot is slightly 
cleft, as is shown for an older scallop (Fig. 27). On both sides of the 
foot in a median position are two vestibules, with several small granules 
rotating inside. These are the otocysts or organs of equilibrium. On 
the dorsal side of the foot, one-third the distance from the proximal 
end, is a prominence with a cleft opening, the byssal gland, the function 
of which has not culminated at this stage. The foot is capable of great 
extension by the contraction of the circular muscles, and is drawn in 
by the contraction of the longitudinal to lie in its normal curved posi- 
tion within the shell (Fig. 18). 

The Adductor Muscles. — The primitive veliger has but a single ad- 
ductor muscle, the anterior. In the dissoconch stage, the posterior 
adductor is the only one present, the anterior having disappeared. As 
is stated by both Jackson (4) and Drew (1), there must be an inter- 
mediate stage where both are present. I have obtained no actual proof 
of this, but in all probability a dimyarian stage, i.e., having two mus- 
cles, must have been reached in the course of development. 



OF MASSACHUSETTS. 



35 



The Gills. — The early veliger has no gills. They first begin to 
develop coincidently with the formation of the foot as simple bars or 
ciliated filaments, capable of extension and contraction from the dorsal 
point of attachment. Starting from beneath the stomach they lie in 
folds along the upper part of the foot. When first seen, at the begin- 
ning of the degeneration of the velum, they scarcely consist of two 
folds, but before the velum has disappeared they number from four to 
five. The edges of the folds are lined with active cilia which keep up 
an incessant motion. These primitive bars, as seen in the prodissoeonch 
(Fig. 18), are the paired beginnings of the inner gills. The outer gills 
develop at a later stage. 

The Mantle. — At the time of the formation of the gills the mantle 
becomes noticeable as a thin, transparent covering just under the shell, 
although it has been functional before this period. By the time the 
dissoeonch stage is reached, the free edge has thickened into fine folds 
and is lined with small cilia. 

The Digestive Tract. — The digestive apparatus of the early veliger 
consists of a funnel-shaped mouth lined with active cilia, leading into a 
broad sac, the stomach, also lined with minute cilia, from which arises 
a two-lobed liver. The intestine is merely a straight tube opening pos- 
teriorly. With the prodissoeonch veliger the digestive tract is obscured 
by the growth of the liver, which has assumed a greenish yellow color 
so that the coils of the intestine are difficult to distinguish. The mouth 
has travelled forward in a dorsal direction, the edges apparently having 
formed the palps, while the ciliated funnel has become the oesophagus. 
The intestine now has one or more coils, and, in order to carry on the 
more complicated process of digestion, opens dorsal to the adductor 
muscle. 

Summary of Veliger Stage. 





Early Veliger. 


Prodissoeonch Veliger. 


Shell, . 














Straight hinge. 


Prominent umbones. 


"Velum, 














Present, . ... 


Degenerate. 


Foot, . 














Absent 


Present. 


Gill-bars, 














Absent 


Present. 


Mantle, 














Invisible, 


Visible. 


Mouth, 














Ventral position. 


Anterior position. 


Palps, . 














Absent 


Present. 


Stomach, 














Simple sac. 


Simple sac. 


Liver, . 

Intestine, 














Small 

Straight 


Large. 
Coiled. 


Adductor muscle, 










Anterior, 


Posterior. 


Size, 










.093 millimeter. 


.18 millimeter. 



36 THE SCALLOP FISHERY 



The Dissoconch Stage. 

The young scallop now enters upon the third stage of its development, 
the period of byssal attachment, which is comparable to youth in man. 
From structural differences of shell, which sharply distinguish it from 
the prodissoeonch, it has been called by Professor Jackson (4) the dis- 
soconch stage. The anatomical changes are so complicated that for the 
purpose of description several arbitrary subdivisions, illustrating suc- 
cessive periods of development, have been made. A table of these 
phases is appended in chapter VII. In the general description of the 
dissoconch period, especially in the section on anatomical development, 
reference is made to these subdivisions. 

The chief characteristics of the dissoconch stage are the habits of 
byssal fixation and crawling. In a preliminary report the writer was 
led to include an intermediate stage between the free swimming veliger 
and the attached scallop, that of a free crawling existence. Later in- 
vestigation has shown that the last two stages practically coincide, and 
that no line of distinction can be drawn. Evidently the power of 
crawling is supplementary to byssal fixation, and is of great service 
to the animal when it wishes to change its location or is torn away 
from its point of attachment. That yomig scallops have the power of 
byssal fixation immediately following the prodissoeonch or at the very 
beginning of the dissoconch stage is shown by those attached to the 
raft spat boxes, described in chapter VII. In many of these scallops 
the dissoconch growth, scarcely one day old, had just started, yet they 
at once attached themselves, by a fine byssal thread, to the sides and 
bottom of glass dishes. 

The subsequent changes in anatomy and shell formation can be 
more readily attributed to a complete change in habits, such as the 
assuming of a stationary life after a free-swimming existence, than 
the transition from swimming to the intermediate crawling stage, such 
as has been suggested by other investigators. Knowledge of the byssal 
attachment in the early part of the dissoconch stage shows that there 
is an abrupt change of life at this period, and gives a new interpreta- 
tion to the structural differences. 

The Set. — The oyster, according to Jackson (4), still possesses a 
velum when it " spats," or attaches itself at the end of the prodissoeonch 
stage, and no foot has developed. " The preliminary fixation," he 
states, " is probably effected by means of the refiected mantle border, 
as described by Eyder, and is then immediately succeeded by a cement- 
ing conchyolin attachment at the extreme edge of the lower left prodis- 
soeonch valve." The scallop, on the other hand, before it sets has lost 
its velum and has developed a muscular foot, which acts as a swimming 
organ during the latter part of the prodissoeonch stage. The set is 
made, not by any fixation of the shell, but by a fine thread, called the 



OF MASSACHUSETTS. 37 

byssuS; formed by a gland in the foot (Fig. 30). It is interesting to 
note that in each case the attachment, though entirely different, comes 
at the end of the prodissoconch period, and that the organs of attach- 
ment and locomotion, owing to the absence of the foot in the oyster, 
are strikingly dissimilar. 

The Shell. — -The shell of the dissoconcb stage (Fig. 19) is sharply 
separated from the prodissoconch by a well-defined growth line and by 
different shell formation. The prodissoconch has a smooth homogeneous 
structure lined with finely concentric lines of growth. The new growth 
is of an entirely different character, as the right or lower valve acquires 
a prismatic structure (Fig. 41), such as was described in Ostrea and 
Pecten by Jackson (4), in which each prism is separated by an inter- 
vening space. The structure on the left or upper valve, while not pris- 
matic, is readily discernible in appearance from the prodissoconch. 
The first indications of coloring in the shell appear during the latter 
part of this period as little dashes of yellow or brown. The dissoconch 
shell has a smooth, even appearance, with no plications, and separated 
by regular concentric gTowth lines, which are used by the writer to 
mark off certain sub-stages. Probably these growth lines, as yet not 
eroded by action of water or subsequent growth, denote daily periods, 
tides or other intervals in shell formation. 

With this stage the hinge becomes for the second time a straight line. 
During the first three sub-stages it is narrow, hardly four-sevenths the 
width of the animal, but later it increases relatively in width, until 
at the beginning of the plicated stage it is nearly the same length. In 
the early stages the hinge line is not absolutely straight, but inclines 
slightly upward at both ends. The inside of the hinge line is set with 
teeth, as described for the prodissoconch veliger (Fig. 22). 

The form of the scallop gradually changes during the dissoconch 
period, as it gTows from .18 to 1.20 millimeters. At first the shell 
rounds out anteriorly, while posteriorly it breaks directly down from 
the hinge line with a slight curve (Figs. 19, 20). The left or upper 
valve elongates anteriorly a slight distance beyond the right, covering 
in this region the byssal notch of the lower valve (Fig. 19). At a 
slightly later stage (Figs. 25, 26) the shell has formed in this region 
a " pseudo ear," which disappears as the animal grows larger, and 
again reappears at the size of 1.50 to 2 millimeters to form the true 
" ears " on both sides of the shell. Meanwhile, the posterior part of 
the shell has increased slightly faster than the anterior, causing the 
prodissoconch to assume a position anterior to the center (Fig. 28). 
Toward the close of the dissoconch stage the scallop loses its elongated 
form and takes on a semicircular appearance (Fig. 31). The various 
changes in form from the early veliger to the 2 millimeter scallop are 
shown in Fig. 77, which consists of eleven concentric camera outlines 
of different sized scallops. 



38 THE SCALLOP FISHERY 

The dissoeoneh scallop differs from the adult, in which the two valves 
are equal, by having the right or lower valve smaller than the left and 
less convex. This is undoubtedly a direct adaptation to its method of 
life during this period, the flat lower valve offering ease and assistance 
in crawling and attachment. Anomia offers an excellent example of 
the flattening of the lower valve in an attached animal, and the rounding 
out of the upper. The same is true of Pecten irradians to a slighter 
extent, as it is not attached so firmly nor for so long a period as Anomia. 

The most interesting feature of the shell formation during this period 
is the development of the byssal notch and groove m the anterior part 
of the lower valve. The notch is the name applied to the indentation 
(Figs. 19—21), while "groove" refers to the hollow formed by the 
growth of the notch (Fig. 25). The notch first makes its appearance 
close to the prodissoconch, indicating that it starts at the time the 
animal " sets." By the time that phase 5 is reached a tooth-like process 
has formed on the notch (Fig. 29). These increase to three in number 
at the end of the dissoeoneh stage, and go as high as five or more in the 
plicated period. Similar teeth are found on the byssal notch of scal- 
lops less than one year old, as new ones are constantly forming, while 
the old are covered by the growth of the shell. Old scallops rarely 
have teeth on the byssal notch. If the shell is broken along the byssal 
groove in an adult scallop an entire ridge of these teeth can be seen 
where they have been covered by the growth of the shell. The use of 
these teeth is miknown, except that they are closely associated with the 
byssus, as is described in chapter IV. under the habit of byssal fi:xatioii. 

The name byssal notch is probably derived from the fact that the 
byssus comes out of the same indentation in the adult. Perhaps at this 
stage a more appropriate name would be foot groove, as that organ, 
in crawling or in spinning the byssus, is thrust out of the opening. 
There is some difference of opinion as to whether the byssus or the 
foot is the cause of the formation of this notch. Jackson (4) says 
that it is formed by the folding back of the mantle, resulting in retarded 
growth in that locality (Fig. 21). Whether the foot or the byssus 
thread was the cause of this retardation cannot be stated definitely, 
although probably both are functional. Although the foot appears 
before the dissoeoneh stage it is used as a swimming organ. The byssal 
notch appears immediately after the prodissoconch stage, corresponding 
with both the byssal attachment and the use of the foot as a erawhng 
organ. Therefore it can safely be concluded that the byssal notch is 
characteristic of this period, and is formed by the combined action of 
foot and byssus. 

The Internal Anatomy. — With the development of the shell, corre- 
sponding changes have taken place in the internal anatomy, rendering 
the scallop better adapted to its new mode of life, j^dult characteristics 
are now manifest, and the animal can be readily recognized as a scallop. 



OF MASSACHUSETTS. 39 

The specific development for each set of organs is given in detail under 
the section on " Anatomical Development/' and it is only necessary to 
give here a brief resume of the more important changes. 

As the animal has entered upon an alternately stationary and crawling 
existence, the foot has become relatively the most important organ, and 
during the early part of the dissoconch stage reaches its maximum 
development in size. The ciliated tip and muscular body render it an 
active organ of locomotion, while the byssus gland provides the scallop 
with a means of attachment. The mantle, at first a simple, curtain-like 
fold with ciliated edges, becomes more specialized by the development 
on its outer edge of a few tentacles and eyes, which give it greater 
sensory functions. The four folds of the inner gills of the prodis- 
soconch increase to twenty-two, and the outer gills make their appear- 
ance before the dissoconch stage is completed. The digestive organs 
increase in size, the liver becoming the most prominent, while the in- 
testine elongates so that the anal opening is on the postero-ventral side 
of the adductor muscle. The posterior adductor muscle, which through 
this period has been capable of great expansion, as is shown in Fig. 23, 
so that the shell is often opened to an angle of 90°, has grown larger 
in circumference and has taken a more central position. The heart, 
consisting of a ventricle and two auricles, with its supplementary cir- 
culatory system, now first becomes conspicuous (Fig. 27). Altogether 
the internal anatomy of the young scallop has passed through the tran- 
sition period from babyhood to the adult, and is now ready to take on 
the final characteristics of the mature scallop. 

Tlie Plicated Stage. 

The plication stage, as the name suggests, marks the beginning of the 
radiating ridges or furrows which give to the scallop its beautiful fan- 
like appearance. These plications do not increase in number as the 
animal grows older. Figs. 33 and 34 show the beginnings of the plica- 
tions in the shell, while Figs. 36 and 37 show a later stage. In the early 
plicated stage the form of the scallop is semi-circular, the height and 
width being aj) proximately the same, while the hinge line is nearly equal 
to the width. The hinge line is now straight, but markings exist in the 
shell showing the former downward slant toward the prodissoconeh, 
which in the early part of the plication period is asymmetrical, but 
later attains a median position, before it is covered by the rounding 
umbones of the shell. The true " ears " of the adult make their appear- 
ance as indentations on the lower sides of the hinge line, anteriorly and 
posteriorly, when the scallop has attained about 2 millimeters in size. 
During this stage they are much less pronounced than in the adult, while 
the hinge line itself is relatively longer, nearly equaling the width of 
the shell. 

The byssal notch, which inclines slightly upward toward the prodisso- 



40 THE SCALLOP FISHERY 

conch, has now become deeper and is lined with several teeth along its 
inner border. The number varies from one to six or more, the older 
teeth being less pointed than the last formed. In Fig. 39 there is a 
secondary fnrrow dorsal to the main groove, and a serrated structure 
near the hinge line, consisting of seven sharply pointed teeth, the origin 
and use of which are unknown. 

The dorsal view of the shell of Pecten at this stage (Fig. 38) shows 
the relative size of the umbones and the hinge line. The left valve is 
deeper than the right and the umbones point slightly posteriorly. The 
line of separation of the prodissoconch and dissoconch growth is sharply 
marked, showing how the two valves, which were close together during 
the prodissoconch stage, have been spread apart by the new growth of 
the valves. This period is just previous to the disappearance of the 
prodissoconch, either by the wearing away of the shell or by the growth 
of the shell. 

The exact duration of the plication stage cannot be given, as the tran- 
sition to the adult is gradual. Perhaps the end of this period should 
come when the animal has attained general adult characteristics. If such 
a definition be tkken, the arbitrary size may be assigned as 4 millimeters, 
for by that time the visceral mass is well defined, completing the adult 
anatomy of the scallop. Unless some standard were taken, it would 
be impossible to tell just when the plication stage ceased and adult life 
began. Another view would have the plication stage followed by a 
period of youth, and consider that the adult life Avas not reached until 
the animal was a year old. This, perhaps, is a better division, although 
the characteristics of the youth and the adult are practically the same. 

The Internal Anatomy. — Few new organs arise during this stage, 
which is mostly concerned in the development of those already formed. 
The most prominent feature is the appearance of the visceral mass 
with the reproductive organs, which a,re first noticeable at the size of 
3 millimeters. The visceral mass grows down from the ventral surface 
of the foot, which becomes relatively smaller with the gTowth of the 
animal. 

At the size of 3 millimeters, the mantle has increased by the formation 
of a set of guard tentacles, which are situated on the perpendicular flap. 
The eyes have increased until they number sixteen or more on each lobe 
of the mantle, while the tentacles have correspondingly increased in 
size and number. The circulatory and the nervous systems have become 
more complicated, to meet the requirements of the growing animal, 
which now has acquired the power of swimming by valvular contraction. 
The digestive system has expanded, the palps becoming ruffled around 
the mouth, and the intestine elongated in the region of the visceral 
mass. The adductor muscle has increased greatly in size and can be 
seen to consist of two distinct portions. By the completion of the stage, 
the animal has attained all the organs and characteristics of the adult 
scallop. 



OF MASSACHUSETTS. 41 



Anatomical Development. 

In order to insure a unified and connected narrative, it was thought 
best, even at the risk of repetition, to trace the development of each 
organ or set of organs separately. Wherever opportunity is given the 
reader is referred to other portions of the report for supplementary 
reading. In tracing the outline of the early life history of the scallop 
the shell has been taken as the unit of description, and therefore its 
development need not be treated separately, and only the soft or 
internal parts of the animal need exemplification. Constant reference 
is made to the various stages outlined in the table in chapter VII,, and 
to the illustrations, so as to present a connected account without unnec- 
essary description. 

The Mantle. — A description of the structure and functions of the 
mantle of the adult scallop is given in chapter II., and it is only neces- 
sary to recapitulate certain points which bear directly upon its develop- 
ment. The mantle is a thin bilobed membrane closely lining the interior 
of the shell and enfolding the body of the animal. The free edges form 
thickened flaps, which are brilliantly colored and lined with rows of 
sense organs, eyes and tentacles. The functions of the mantle are: 
(1) shell secreting, as the growth of the shell is due to the secretions 
from the mantle; (2) protective, as it enfolds and guards the body, and 
is largely instrumental in swimming and feeding; (3) sensitory, as the 
numerous tactile appendages and the circumpallial nerve render it 
sensitive to the slightest stimulus. 

There is a steady development from the primitive mantle in the young 
scallop to the highly specialized organ in the adult. It can be deduced, 
from the changes which take place during the embryological and post- 
embryological development, that the early ancestor of the scallop did 
not have such highly specialized functions, which only developed when 
the animal assumed its present dangerous mode of life, where it depends 
upon its nervous mechanism to warn it of impending danger. 

The primitive mantle of the young scallop is a simple bilobed fold 
joined along the hinge line, and is first visible in the prodissoconch or 
late veliger stage. In the early veliger, although probably present to 
enable the formation of the embryonic shell, it was not noticed. It 
evidently attains prominence during the prodissoconch stage as a definite 
mantle, common to all lamellibranchs, similar, except for the crenulated 
edges, to that of the adult quahaug. At this time it appears entirely 
separate from the degenerate velum, wJiereas in the early veliger it was 
indistinguishable. The animal can extend the mantle slightly beyond 
the shell, and by means of retractor muscles withdraw it to about two- 
thirds its natural size. Even at this early period the mantle serves as a 
sensory organ, as the edges are lined with minute cilia and simple 
folds are already noticeable on the borders. 



42 THE SCALLOP FISHERY 

.During the clissoeoneh or attachment stage, the mantle first takes on 
characteristics Avhich differentiate it from the early stages of other 
forms. The edges become more folded and knob-like projections grad- 
ually form at definite places on the border, some to form tentacles, 
others the eyes of the scallop. ( The development of the eyes and tenta- 
cles will be considered separately under " Sensory Organs.") The 
retractor muscles become stronger, and the mantle is now capable of 
greater extension and contraction, withdrawing at points where irritated. 
As the animal grows larger the number of retractor muscles of the 
mantle increase and are attached in a widening semi-circle far down the 
interior of the shell, so that only the outer portion of the mantle hangs 
free. 

Another important functional change takes place when the so-called 
flap of the mantle is formed. This is a thin outgrowth in a perpendicu- 
lar direction along the entire edge of the mantle, except just beneath 
the " ears " near the siphonal openings. The flap, when first formed 
during phase 6, is entirely plain, but soon is ornamented with a row of 
small tentacles called by Jackson (4) " guard tentacles." With the 
formation of the guard flap the animal has become a specialized scallop, 
differing from other lamellibranehs. The valves are now held apart, 
when resting, in such a way that the opposite flaps almost close the 
intervening space. Water can be taken in and shot out of the shell, 
giving the scallop the power of swimming. 

Closely allied in function with the guard flap is the formation, during 
phase 5, of what is known as the pseudo-siphon, which arises as a 
transparent conical projection from the median posterior border of the 
mantle. This organ is formed by the concrescence of the mantle edges, 
and is not a true siphon, as is found in the clam and qu:ahaug. Func- 
tionally this pseudo-siphon acts as an exeurrent canal to eject water 
from the shell. Although it is not used for the jDurpose of swimming, 
as is the case with the same region in the adult scallop, it assists the 
animal at this period of life in crawling, as simultaneously with the 
contraction of the foot a stream of water is ejected from the pseudo- 
siphon. After each flow of water the siphon is retracted again, to be 
extended when the next stream is forthcoming. The pseudo-siphon 
disappears before the scallop reaches adult size, and is evidently only 
functional during the crawling period. 

The mantle, particularly the edge, is beautifully hued with many 
colors. The mantle of the scallop at flrst is a transparent white, which 
gradually takes on the colors of the adult mantle. The intensity of the 
color varies greatly in the different scallops and is as unexplainable as 
the variety of colors in the shell. 

The Sense Organs. — The scallop has a well-developed sensory sys- 
tem of specialized parts, each of which contributes to the maintenance 
of life and to the protection to the animal. 

(a) Tentacles. — The tentacles in the adult scallop line the border of 



OF MASSACHUSETTS. 43 

the mantle. There are two kinds: (1) the large, highly extensible tenta- 
cles, lining the outer edge of the mantle, called by the writer " mantle 
tentacles" to disting-uish them from (2) the inner or "guard tentacles," 
which lie on the edge of the perpendicular mantle flap. The " mantle 
tentacles " comprise several rows, apparently without any definite 
arrangement in the adult. When extended they have the appearance 
of long, slender white bars covered with minute conical projections, 
each tipi^ed with a hair. The '' guard tentacles " differ from the former 
in extensibility and function. They extend nearly the entire edge of the 
mantle flap, except in the region of the two siphonal openings below 
the " ears," and evidently act as strainers to keep out foreign substances 
from the mantle chamber. 

The first specialization of the mantle border, the tentacles, appear 
when the growing condition of the animal demands sensitory functions. 
They appear soon after the scallop passes the size of .5 of a millimeter, 
just previous to phase 5, when they can be seen fairly well developed. 
The first tentacles were noted as conical papillary projections .04 of a 
millimeter in height, tipped with single cilia (Fig, 44a) on the border 
of the ciliated mantle. Soon another rises close to the first, or more 
likely there is a division into two with a granular core between (Fig. 
44b). The growth continues by repeated subdivisions and the extension 
of the core part of the mantle until a colony of these projections is 
formed (Fig. 45), covering a single tube of blood spaces, nerves and 
tissue, the tentacle proper. The papillary projections radiate from the 
stalk in such a manner as to give it the appearance of a pineapple 
(Fig. 46). Such projections are noticeable on the tips of the tentacles 
during stage 5 (Fig. 29). 

The first tentacles to form are in the ventral region of the mantle 
(Fig. 27). When the young scallop has nine large tentacles on each 
mantle lobe, it has seven eyes, which alternate with tentacles. At this 
stage there are nine slight secondary tentacles which arise between the 
large ones and in definite relation to the eyes (Fig. 29). As the scallop 
grows the tentacles increase rapidly by this method of interpolation, with 
the result that there finally is apparently no definite arrangement of 
tentacles and eyes. The first nine tentacles may be styled primary, as 
they are much larger than the others, which, taken in the order of their 
occurrence, are called .secondary, tertiary, etc. It is interesting to note 
(Fig. 29) that no primary tentacle is near the central region of the 
pseudo-siphon, but that there is one on each side. In scallops of IV2 
millimeters these tentacles when extended measure two-thirds the height 
of the animal. The " guard tentacles," on account of their function, 
are quite different in appearance from the "mantle tentacles," being 
less extensible and heavier. 

There are several uses for the tentacles of the young scallop, especially 
the primary, which are not functional in the adult. In -floating, the 
small animal opens the shell, extends the tentacles to full length, and, 



44 THE SCALLOP FISHERY 

turning the body with right valve uppermost (the reverse of the natural 
position), maintains itself on the surface of the water. This habit has 
been observed in numerous cases in the aquarium in which scallops 
were confined. In scallops over 1 millimeter it appears to be accom- 
plished by the spreading of the tentacles. 

Observers, as Jackson (4), have stated that the animal is assisted by 
the tips of the tentacles in crawling, more particularly in climbing, 
during which the tentacles cling to the sides of the glass. Whether the 
extension and clinging of the tentacles is any great help to the foot in 
climbing is a matter of doubt, but they undoubtedly rest on the glass 
and are extended during both swimming and crawling. 

The chief function of the tentacles is sensory. Often the tentacles 
of the adult do not respond to external stimuli, as would naturally be 
supposed, and in the ease of repeated stimulation often fail to react 
at all. In scallops of 2 millimeters the tentacles may be made to contract 
separately by mechanically stimulating one at a time. This nervous 
reaction is not general, but if the whole animal is suddenly jarred all 
the tentacles are Avithdrawn with surijrising swiftness. The tentacles 
of scallops of- this size render the animal more sensitive than the 
smaller scallops, which do not have the full development of the tentacles. 
Thus the sensory nature of the tentacles is proven, and the subsequent 
inactivity of the large adults must be accounted for in other ways. 

(&) The Eyes. — The most prominent feature of the mantle border 
is the fringe of brightly pigmented eyes, which are thickly scattered 
along the edge. In the adult there is great variation in the number, 
size and order of arrangement. These eyes are comparable with those 
of higher animals, and evidently have a sensory function. 

As stated by Drew (1) the eyes are closely allied to the tentacles, and 
are in fact derived from the same source, being nothing more than 
modified tentacles. Their situation, origin, time of appearance, arrange- 
ment, all indicate that the eyes and tentacles are fundamentally the same. 

The eyes make their appearance during phase 5, when the first or 
primary set is developed just after the primary tentacles are formed. 
The two lower or ventral eyes are formed first, then the eyes near the 
hinge line, and the intermediate ones soon after, numbering seven on 
each lobe of the mantle. The color of the eyes varies at this age from 
a brown to a blue. As can be seen in Fig. 29, the primary eyes and 
tentacles are arranged defi]iitely, the eyes being situated on slight pro- 
jections on the outer fold of the mantle between the tentacles. The 
successive development of the eyes is like the tentacles by the formation 
of secondary, tertiary, etc., sets between the j3rimary eyes, at first 
alternating with the tentacles, but later apparently without definite 
arrangement. Although the visual function of the scallop's eye has 
been a matter of much dispute, there is but slight question that the eye 
has its use as a sensitory organ. 



OF MASSACHUSETTS. 45 

(c) The Otocyst. — The otocyst, or organ of equilibriirm, is situated 
in the foot in the young animal. It is first seen in the scallop of the 
prodissoeoneh stage as two vestibules of small size, one on each side 
of the foot. Inside the circumference is a clear fluid in which several 
small granules are constantly revolving (Fig. 20), evidently due to 
ciliary action. These remain prominent in the foot as long as that 
organ is relatively the largest part of the body, but are gradually lost 
sight of in the visceral mass of the adult scallop. 

The Gills. — The gills form during the transition period from the 
early veliger to the prodissoeoneh stage, when they are observed as 
simple primitive folds lined with vibrating cilia. At the beginning of 
the dissoconeh stage the gill is a bar folded into four simple filamentous 
processes, covered on the outer edge of the folds by rapidly stroking 
cilia (Figs. 18 and 20). Later stages show that the bar filaments are 
added ventro-posteriorly, first appearing as bud-like processes. The 
gills then consist of simple bar filaments so arranged with the longer 
ones dorsal that the whole gill has a semi leaf -like appearance. At the 
end of the dissoconeh period these filaments number between 20 and 25, 
while the more mature dorsal bars became enlarged at the free end, 
due to their turning back upon themselves. At this time there are two 
gills, one on each side of the body, which are the inner gills of the adult. 
This later gTowth marks the beginning of the inner lamella although the 
filaments are still separate. The scallop is about 1 millimeter (about 
%5 of an inch) in size at this time. 

The next change is the formation of two outer gills, which mark the 
characteristic structure of the adult. Just previous to the appearance 
of the outer gills the animal has two inner gills of about seventeen 
filaments. Small *' buds " arise on the upper edge at the posterior end 
of the gill, and increase rapidly in size and number. It is curious that 
the development of the outer gills starts at the posterior instead of the 
anterior end, exactly reverse to the formation of the inner gill. In a 
1^-millimeter scallop sixteen filaments were counted on the outer gill, 
in a 1.8-millimeter scallop twenty-eight, and by the time the animal had 
reached the size of 3 millimeters the gills had the same appearance as 
in the adult. The inner gills are reflected inward, the outer gills fold 
outward to form the second lamella. 

The later changes are more complicated and not so conspicuous. The 
filaments appear to become united, but on close examination this union 
is found to be due to the interlocking of ciliated discs on the posterior 
and anterior sides of each filament, giving the appearance of interfila- 
mental cross bars. The filaments are joined in groups or bands of seven 
or eight. A 4-millimeter scallop has about ten bands, a 5-millimeter 
specimen twenty-five. The lamellae are also attached at intervals by a 
fine septum. 

The gills are at all times very sensitive. When touched with a pencil 



46 THE SCALLOP FISHERY 

they immediately contract. If a few drops of formalin are placed in 
the water near a small scallop a sudden clapping of the valves frequently 
shoots out a detached portion of the gills. 

The Adductor Muscle.- — According to Jackson (4) the revolution of 
the axis has brought about the loss of the anterior and retention of the 
posterior adductor muscle in the adult Pecten. Naturally, as with the 
oyster, there is one period of life, the early veliger stage, when the ante- 
rior adductor is present. Then follows an intervening stage where 
both are presumably present, and finally, by the time of the dissoconeh 
stage, the anterior adductor has disappeared. Sharp (15), like Jackson, 
favors the view that the mechanical shifting of the axis of the shell has 
caused the atrophy of the anterior and the subsequent enlargement of 
the posterior adductor. In the adult the muscle is formed of two parts, 
a large anterior and a small posterior division. The relative increase in 
size of the muscle between 3 and 10 millimeter scallops is more rapid 
than the formation of the shell, the muscle increasing sixteen times, the 
shell only eleven times, in volume, and is possibly due to the need at 
this period of a larger muscle. 

The Foot. — - As the functions of the foot are given in chapter IV., 
under " Locomotion " and " Attachment," little needs to be said here. 
From the relatively largest organ in the scallop during its dissoconeh 
stage, the foot rapidly becomes smaller, owing to degeneration and lack 
of use, until in the adult it is but a small projection on the antero-dorsal 
surface of the visceral mass. 

The Visceral Mass. — The degeneration of the foot marks the growth 
of the visceral mass, which contains the reproductive organs and the 
coils of the digestive tract. It is first noticeable to the naked eye in the 
3-millimeter scallop as a mere speck on the ventral surface of the foot. 
The reproductive organs are the last to mature and the last to be of use 
to the animal before its decline, which theoretically starts at the com- 
pletion of spawning. Even at this early stage it is covered with the 
black jDigment so prominent in the adult. A white streak running along 
the aiaterior edge marks the situation of the testes. The rest of the 
mass is covered with the pigment. The surface area of this mass for a 
13-millimeter scallop is ten times greater than for a 3-millimeter animal. 
The intestine does not form a part of the mass until the scallop has 
attained a size of 8 millimeters, when the coils are enveloped. The 
visceral mass continues to increase in size until in the adult it is the 
largest part of the body. 

The Digestive System. 

(a) The Palps. — The palps are formed soon after the disappearance 
of the velum, and there possibly may be some connection between the 
two as the velum disappears in the vicinity of the palps. At first they 
are simjole folds, as in the average lamellibranch, and not until later do 
they assume the ruffled form which is characteristic of the adult. 



OF MASSACHUSETTS. 47 

(&) The Mouth and (Esophagus. — The primitive mouth and oesoph- 
agus in the veliger consisted of a simple ciliated funnel leading into the 
stomach. At this period the edges of the mouth were covered with cilia, 
and the palps had not made their appearance, the only fundamental 
difference between the mouth of the veHger and of the adult. 

(c) The Stomach. — The stomach of the veliger can be discerned 
beneath the liver through the transparent shell. The walls are lined 
with cilia. The adult stomach is more specialized by the formation at 
the posterior end of the articulating receptacle for the head of the 
crystalline style, by its larger size, and the ridges and folds which line 
its inner surface. Its development is gradual with the rest of the soft 
parts of the scallop, but cannot be traced in the young scallop after the 
veliger stage, owing to the dark covering of the liver. 

(d) The Liver. — The liver appears in the veliger stage as two glands 
on each side of the stomach, and rapidly spreads out to cover that 
organ, so that in the developed veliger the most conspicuous object is the 
large liver mass in the center of the animal, with its granular colored 
appearance. As the scallop grows older, the liver takes on a darker 
color, which in the adult is an extremely dark brown, whereas in the 
young scallop, even up to 15 millimeters, it is a light brown or occa- 
sionally a yellow brown, 

(e) The Intestine. — The intestine of the veliger when first formed 
is a simple tube curving downward and backward from the stomach. 
In a few hours the digestive processes have necessitated greater use of 
this organ and it has accordingly elongated by forming a coil in the 
upper part of the mantle chamber above the stomach and liver. The 
entire length of the tube is lined with cilia, and the food particles can 
be seen rotating within. The successive development of the intestine, 
exclusive of the formation of the crystalline style, which lies in a folded 
groove in the portion near the stomach, is chiefly that of elongation by 
means of coiling. When the scallop attains the size of 8 millimeters 
the coils of the intestine are inclosed by the visceral mass, or rather 
are seen to be enfolded in that substance, and are carried ventral as tlie 
mass increases in size. The anal opening passes during this development 
from a position dorsal to the adductor muscle to a more ventral situa- 
tion in the adult, thus further increasing the length of the digestive 
tract, which passes through the central chamber of the heart. 

Coloring of the Shell. 
The numerous color variations in the shells of young scallops render 
them conspicuous among other objects on the tidal beaches. Scallops 
are found of all shades, ranging from the plain color to the striped 
varieties, with hardly two alike, and are on this account often gathered 
for ornamental or decorative purposes. The popularity of the scallop 
shell is ancient, as history tells us that this shell was the device on the 



48 THE SCALLOP FISHERY 

shield of many a crusader, and that through all ages it has been regarded 
as an object of beauty. 

Naturally, various questions on the subject of shell coloration arise, 
such as (1) the nature of the coloring matter; (2) where and how it 
appears; (3) the variations; (4) do scallops change color? (5) is color 
due to inheritance or environment? In connection with the growth 
experiments on young scallops the following notes were made. 

Coloring Matter in the Shell. — In scallops from 3 to 10 millimeters 
the brown coloring matter is the predominating shade. When mounted 
on a slide after having been treated with acid the colored shells leave a 
brown outline of various intensities on the glass, according to the 
depth of the color, while the pure white are barely discernible in outline, 
showing that the brown coloring matter resists the action of the acid. 
Other colors, as black and red, are of different origin and disappear 
under the action of acids. 

The Appearance of the Color. — The lower or right valve of the 
scallop shows the color best. The upper valve is usually darker, of 
plainer hue, and covered with growths such as eel grass, sea lettuce, 
Enteromorpha and numerous smaller plant forms. In the young scal- 
lops the color 6f the two valves is the same, and only when the upper 
becomes coated over is any difference apparent. In the adult the lower 
valve is much lighter in color than the upper. 

The time of appearance varies greatly. Albino scallops, which do 
not seem to have any coloring matter in the shell, are found in all sizes 
up to 1^ inches. As they grow older the pure white color takes on 
a yellowing or gTayish hue. Scallops the size of the head of a pin may 
have more color than scallops the diameter of a lead pencil. The pro- 
dissoconch is unpigmented; occasionally in the dissoconch stage little 
spots of color make their appearance, but no decided coloration takes 
place before the plications begin to form, when the scallop assumes iu 
a minor degree the color patterns of the adult. 

Color Variation. — The color of the shell varies greatly, especially 
with the young. All varieties from a pure white to a grayish-black, 
as well as a red variety, can be distinguished. The common marking 
is a mottled or striped appearance, undoubtedly the intermediate forms 
between the pure color types, as it is possible to arrange a series of 
shells showing these gradations. The color marking of the young seal- 
lops offers an excellent field for the student of variation. 

Young scallops from % to 10 millimeters can be readily divided into 
two main classes, using color as a basis of separation. Some are daric 
brown with a white fringe, while others range from a light yeUow to a 
transparent white. It seems strange that scallops of the same set and 
size should present so much difference in color, and that different colors 
are often found on the same place of attachment. 

In white scallops 2 to 3 millimeters a yellow pigment is frequently 
found in the grooves between the ridges, whereas in the adults these 



OF MASSACHUSETTS. 49 

furrows are colorless. Yellow markings are found on these small scal- 
lops below the hinge line in scattered patches about the umbo. 

Do Scallops change Color as they grow older? — In 1906 the follow- 
ing experiments were made: Scallops of the 1906 set, ranging from 
10 to 20 millimeters, were obtained from Stage Harbor, Chatham. 
These were sorted according to color and placed in wire baskets and 
suspended from the raft at Monomoy Point. On Sept. 7, 1906, they 
were put on the raft, and on Oct. 23, 1906, the color changes noted. 
A similar experiment was made with smaller scallops, about 3 milli- 
meters in size, from August 15 to September 15. 

These two observations indicate that there is a slight change in color 
from white to medium and from medium to dark, or that the scallop 
shell acquires as it grows older a darker shade. The dark scallo]DS 
ahvays remain the same, while the light-colored ones gradually take 
on a darker hue which never becomes very intense. Scallops betAveen 
3 and 12 millimeters vary in deepening their color, some requiring one 
week, others three, before any appreciable change is noticeable. 

Is Color hereditary or due to the Environment? — The color of the 
shell seems to be an inherent quality and not influenced radically by 
the environment. An orange-colored scallop is always orange color, 
as has been shown by keeping record of the same colored scallops in 
wire baskets, and a small orange-colored scallop will always remain 
the same color, no matter how large it becomes. Color is not wholly 
unaffected by environment, as modifying changes occur; but in the main 
it is a constant quantity. The nature of the surface to which the scal- 
lops are attached does not seem to determine the color of the shell, as 
on light-colored wooden boxes 150 out of 1,100 scallops were dark 
colored, while the remainder of the scallops, which measured from 2 to 
3 millimeters, were of a lighter hue. This shows that environment does 
not regulate the color formation of the shell, as both dark and light 
colored scallops are found on the same surface. It is perhaps worthy 
of notice that the majority, 86V2 per cent., were light colored, while 
the rest, only 13^/2 per cent., were dark. The conclusion is that environ- 
ment, while perhaps tending to modify the coloration, does not deter- 
mine the true color of the scallop, which is an inherent quality in the 
animal. 

An interesting experiment could possibly be made in regard to color 
inheritance if certain mechanical difficulties in the line of artificial 
propagation could be overcome. It would be of scientific interest to 
know whether scallops of a certain color would transmit this color to 
their offspring, and if so in what proportions. To accomplish this it 
would be necessary to have inclosed spawning ponds in which the 
scallops of the required color could be separated from the rest. At 
present, owing to the difficulties in the breeding of scallops, this is not 
possible, and an experiment of this nature will have to be postponed 
until artificial breeding is more fully perfected. 



50 THE SCALLOP FISHERY 



CHAPTER IV. — HABITS. 

The story of the scallop would hardly be complete without some 
mention of its interesting and curious habits, which not only explain 
the anatomical structure, but also throw further light upon the life 
history. The methods of life of the young scallop are for the most part 
different from those of the adult, and are typical of stages in the de- 
velopment of the animal. A change in the function of an organ causes 
a corresponding change in its form, and practices once useful are dis- 
carded for others better adapted to the needs of the growing animal. 
Throughout early life can be traced a steady development, culminating 
in the adult method of life. For this reason the habits of the young, 
with the exception of swimming and resting, have been considered 
separately in the following chapter, and as far as possible arranged in 
logical sequence. 

Attachmeistt. 

After the free swimming period of its early existence, one of the most 
prominent habits of the young scallop is the power of attachment^ 
which occurs at. the completion of its embryonic existence. This func- 
tion not only proves a great help in gTOwth, marking a new era in shell 
formation, but renders the immature animal less liable to attack from 
its numerous enemies. 

The Set. — The " set " takes place when the young scallop attaches 
itself to any foreign object by means of threads secreted from a gland 
in the foot. The animal, at the proper time, settles or strikes against 
some object in the water, and clings to the point of attachment with 
its foot until the thread or byssus is spun. The frequency of " set " on 
eel grass is best explained by the hypothesis that the swimming scallop 
at this critical period of its life is carried by the current against the 
upright blades, where it clings with the foot until the byssus thread 
is formed. Larger scallops have been observed to "swim to the sides of 
the aquaria and support themselves on the slippery glass by the foot 
alone until the attachment by the byssus was accomplished. The great 
numbers of young scallops found on the sides of sjoat boxes lowered 
from a raft moored in 20 feet of Avater show that the means of first 
attaining this attachment was by clinging with the foot when the animal 
came in contact with the box. 

Young scallops attach themselves to eel grass, shells, stones, etc., but 
are generally first noticed by the fisherman on eel grass or sea lettuce, 
where they remain until they reach adult age. Scallops are found on 
both the upper and the under side of eel grass, usually 3 to 6 inches 
from the bottom being the locality of the heaviest set. Ulva (sea 
lettuce) seems to offer a better place of attachment than eel grass, as 
it may be carried for miles by the currents and " seed " scallops may 



OF MASSACHUSETTS. 51 

be transferred in this way from one locality to another. Shallow flats 
covered with thick eel grass are usually the most productive of heavy 
" sets," although the exposed nature of these flats during the winter 
often causes a severe mortality among the young scallops. 

The exact conditions governing the set in any one locality are diffi- 
cult to observe. The primary requisite is something to which the attach- 
ment can be made. This is usually eel grass. In a number of cases 
heavy " sets " are found in the still water on the sides of a swift 
current. This is often the case at the entrance to harbors where eel- 
grass flats line the channel. The spread of the incoming or outgoing 
waters carries with it the young larvae, which, striking the eel grass in 
the still water, settle upon the waving blades. 

The Byssus (Fig. 43).- — The young scallop after its free swimming- 
existence attaches itself by slender strands of hard, gelatinous material 
to the first suitable object with which it comes in contact. This bundle 
of threads is called the byssus, and is similar in function to the anchor- 
ing strands, the " beard " or " weed," of the common black mussel. 
The number of fibers composing the byssus depends upon the size of 
the scallop and the length of time attached, as but one thread is formed 
at a time, and the total number is not at once completed. As the scallop 
increases in size, the number of strands increase in proportion to the 
added weight. The environment may also determine the strength of 
the byssus, as scallops exposed to the strong winds and wave action 
necessarily need more anchoring strands. 

The byssal threads pass from a gland in the foot out through an 
indentation in the lower or right valve of the scallop to the surface of 
the foreign object to which they are attached by minute discs. This 
indentation, directly under the anterior " ear," is the so-called byssal 
notch, which has already been described in chapter III. Along this 
groove are little projecting teeth or knobs, which develop in the later 
part of the dissoconch stage soon after the attainment of the byssal 
attachment. The use of these teeth is not known, but appears to be 
related to the byssal habit. Possibly they are of use in separating the 
strands. In scallops under one year of age these teeth number four to 
five, but in the majority of old specimens they are entirely absent, 
evidently disappearing when the byssus becomes practically useless, 
as the last formed teeth are rounded instead of sharply pointed. The 
manner of disappearance is readily shown by breaking the valve along 
the byssal groove and observing the line of teeth which have been en- 
veloped in the adult shell. As they are formed at the same time that 
the byssus becomes functional, and disappear when that organ is no 
longer of use, there seems little doubt that their use is closely correlated 
with that of the byssus. 

The following excellent description of the process of byssal fixation 
is given by Jackson (4) : — 



52 THE SCALLOP FISHERY 

Lying on the right valve, the foot is extended on the surface of the dish, 
the flattened distal portion taking a firm hold as if about to crawl. This 
position is maintained for a moment or two and then the foot is withdrawn 
within the body; by the motion of retraction it draws out, or spins, the 
byssal thread, which the creature had fixed to the surface of the dish while 
the foot was laid closely against it. Soon the foot is again extended, pressed 
flatly against the dish, and another byssal thread is spun. The second 
byssal thread is always attached at a point a little removed from the point 
of fixation of the first thread; sometimes the two are separated by a dis- 
tance of two or more millimeters. Additional threads may be spun; but 
three was a common number with specimens in confinement. Those on the 
bar, especially the larger individuals, frequently spun a large number of 
threads in the byssus. The byssal gland is situated in a proximal cleft-like 
depression in the foot separate from the more distal cleft-like depression 
which serves the animal in crawling, so that between the two there is a 
slight interspace without a cleft. Frequently when forming the byssus the 
foot may be arched up in this interspace, the hold being maintained by the 
tip of the foot and at the same time the byssal cleft being pressed closely 
against the glass, so as to make the fixation of the byssal thread. While 
spinning the byssus the scallop is preoccupied, and pays little attention to 
pricks or stimuli which at other times would meet with immediate response. 

The following notes, which give additional information as to the 
length of time, were made on a 6-milIimeter scallop confined in a small 
aquarium (Figs. 58-60). 

The scallop lay in an unnatural position on its left or upper valve 
on the bottom of the glass dish. At 10.15 it extended its foot perpen- 
dicular to its body, lashing it to and fro with a wavy motion, until it 
was extended to its full length. Then, at 10.151/2, it placed the tip on 
the bottom in a cautious manner. Soon after attaching the tip the 
scallop contracted the foot, snapping its valves in such a way as to force 
a jet of water from the posterior edge of the shell. This movement 
forced the body ahead with a partial turn. The scallop thereupon with- 
drew the foot, shooting two additional jets of water from the posterior 
pseudo-siphon. During these maneuvers a one-stranded byssus had been 
formed and was completed by 10.17. The byssus gland, meanwhile, had 
been in contact with the bottom of the dish, and the thread was formed 
by the opening of the groove and the hardening of the horny mate- 
rial by contact with water. Another scallop of the same size was twice 
observed to spin a byssal thread in four minutes, each time swimming- 
through the water with foot extended in the interval between the attach- 
ments. 

Period of Attachment. — The scallop can cast off the byssvis at will, 
and soon spin another. The threads are broken off at the byssal gland, 
where they are closely united, and left adhering to the object of attach- 
ment (Fig. 43). This habit is altogether voluntary or under the effects 
of external stimuli. The early life of the scallop thus consists of a 



OF MASSACHUSETTS. 53 

series of attachments and dislodgments, with intervening periods of 
crawling or swimming. 

The power of byssal fixation is first noticeable at the beginning of the 
dissoconch stage, when the young animal is found on eel grass and 
other objects. The free swimming period of the veliger has just passed 
and the scallop has entered upon a new existence, that of crawling 
and attachment. The scallop retains the power of byssal fixation 
throughout life, but seldom makes use of it after the first year. Scallops 
fifteen to sixteen months old have been frequently observed fastened to 
eel grass and to each other, showing that byssal attachment even at this 
late period in life is by no means uncommon. Perhaps scallops over 
one year old find little use for the byssus, as, owing to their size, there is 
less danger of their washing ashore in heavy winds. A twelve-month 
scallop has been seen to attach itself to the bottom of the aquarium 
twice within forty-eight hours. 

Observations on the Attachment. — The byssal thread is strong and 
flexible, as the 6-millimeter scallop when firmly attached can be revolved 
at least 360° without breaking the strands (Figs. 52-54). 

A curious attachment was noticed in a 2V2-iiiillimeter scallop on Aug. 
3, 1908. The scallop was hanging by a byssal thread apparently from 
the surface of the water. The distal end of the byssus seemed attached 
to a small bit of mucus on the surface of the water, which was bowed 
down by the weight of the scallop. The valves of the little animal were 
apart, the tentacles extended, and the foot was lashing around with a 
wavy motion. The point of attachment was touched with the tip of a 
pencil, whereupon the byssus stuck to it so that the scallop could be 
raised to the surface and towed around the dish. The pencil point was 
then lowered gently in the water and the scallop remained suspended 
from the surface as before. This was repeated with the same result. 
The pencil was thrust through the water until it touched the scallop, 
which cast off its byssus at once. 

Young scallops swim with the foot extended, and if the foot comes 
in contact with an object, such as the side of the aquarium, the animal 
claps the valves rapidly, as if to keep its balance until the foot becomes 
firmly attached. The movement might be likened to the fluttering of a 
hen when flying on to a roost. The foot is then drawn in, and the 
animal remains hanging to that corner of the shell by means of a quickly 
spun byssus. If the scallop strikes the side of the aquarium with any 
other portion of its body it does not have the power or perhaps the 
intelligence to swing the body around so that the foot will strike the 
glass. This observation shows that the scallop of 2 millimeters and over 
gains its position on the sides of the aquarium as frequently by swim- 
ming as by the more laborious method of crawling up the sides. 

Value of the Attachment. — The value of the byssus as a protective 
factor is at once apparent when one considers the rough conditions to 



54 THE SCALLOP FISHERY 

whicli the scallop is often subjected. If it were not for some means of 
holding fast to the eel grass or other supports, the heavy storms would 
wash the small animals asliore. So possibly this power has been devel- 
oped by natural selection for the protection of the scallojD. Also, nature 
has acted wisely in making the attachment and climbing powers of the 
scallop supplementary, as the climbing habit is necessary to enable 
the scallop to reach a place of attachment, or, when attached, to find a 
better location. 

Spat Collecting. — The attachment period in the life of the scallop 
naturally offers the best opportunity for the capture of " seed." When 
this period of life is reached in the ease of the oyster, the planter puts 
into the water large quantities of shells, on which the young oyster may 
" set " or permanently attach itself by a calcareous fixation. The 
scallop, unlike the oyster, has no power of calcareous fixation, and the 
byssus is not a permanent attachment. If found desirable, old nets, 
frayed rope, boxes, etc., hung in a moderate current, should furnish an 
excellent means of collecting spat. Although scallop larvae were plenti- 
ful in the water, no natural set on the eel grass occurred during the 
summer of l^OQ' in the Powder Hole at Monomoy Point. Nevertheless, 
on boxes and frayed rope, lowered for spat collecting from a raft, 1,200 
small scallops were obtained in .a few square feet of surface. At the 
present time there is no distinct need of sjDat collecting, as " seed " is 
superabundant in many localities. The young dissoeoneh scallops usu- 
ally are attached by one byssal thread. 

Locomotion. 

The young scallop depends greatly upon its powers of locomotion to 
enable it to maintain the struggle for existence, to seek new fields and 
to escape its enemies. Early movement is shown by the swimming of 
the ciliated embryo, an entirely distinct process from the same function 
in the adult scallop. Between intervals of attachment it moves by 
crawling with the foot either along the level or clinging to perpendicular 
surfaces, a considerably slower method than the earlier habit. Later, 
the swimming powers of the adult gradually appear, although the 
scallop still maintains its crawling powers. There is a gradual develop- 
ment in its methods of locomotion comparable to changes in its life, 
each of which are adapted to the special needs of the animal. 

Crawling. — The scallop, long before it lost the faculty of swimming 
with its foot, had the power of crawling, although it did not wholly rely 
upon this method. When the body became too heavy to swim success- 
fully with the foot, the animal depended entirely upon the latter means 
of locomotion. Later, when the swimming habits of the adult made their 
appearance, the young scallop used both, assisting the act of crawling 
by shooting a stream of water from the posterior edge of the shell in 
unison with the contraction of the foot. Crawhng is accomplished by 
three muscular actions of the foot, extension, holding and contraction 



OF MASSACHUSETTS. 55 

(Figs. 55-57). Before starting to move the scallop projects its foot, 
waving it several times around, as if to reconnoiter. Then, suddenly 
becoming bold it stretches out this organ in a decided manner. The 
foot is elongated about the length of the body by the contraction of 
the circular muscles, which is called a " thinning wave " by the Ger- 
man. The free end is firmly set by a sucker-like arrangement, and 
a " thickening wave," caused by the contraction of the longitudinal 
muscles, passes toward the shell. The foot movement is roughly com- 
parable to the creeping of an earthworm. The shortening of the foot 
jerks the shell forward, the movement being strengthened by the clap- 
jDing of the valves, which send out a current of water posteriorly from 
the pseudo-siphon, as is indicated by the moving specks of dirt in the 
water. The valves shut when the longitudinal muscles contract and 
open with the contraction of the circular muscles, giving a jerky motion 
to the crawling. 

The scallop may change its direction in crawling by setting the tip 
of the foot to either side of the line of motion. When the foot contracts 
the shell is swung around very effectively. As the animal has never 
been observed to crawl backward, a frequent maneuver with young clams 
and quahaugs of this age, it probably reverses its direction by a series 
of these movements. The animal often changes its base of crawling 
from the face of the right valve to the free edges of both valves. In 
this case the valves are so tilted that the posterior portion of the free 
edge is uppermost, thus making the anterior posterior axis perpendicular 
to the surface on which it crawls. (The above observations were made 
on 1 to 2 millimeter scallops.) 

An early dissoconch scallop (phase 4) was observed to take a peculiar 
position on the bottom of a watch glass. It raised itself on to the edge 
of the shell with the anterior end high in the water, the foot extended, 
waving back and forth. Whether it did this by other aid than the lash- 
ing of its foot could not be ascertained, but it gracefully rose on edge. 
A similar maneuver was observed in a iy2-millimeter scallop. Evidently 
this habit is useful in turning over when the young scallop finds itself 
on the wrong valve. 

In a young scallop about 1 millimeter in size (phase 5) the following 
rate of traveling was observed. The heart beats faster when the scallop 
is crawling than when the animal is resting. Occasionally all visible 
cardiac movement ceases for short periods during the resting stage. The 
rate of beat Avhen crawling is about 100, when resting 85, per minute. 
The first series of continuous movements permitted the animal to cover 
the space of 5 millimeters in thirty seconds. On a second trial the 
scallop was able to cover the same distance in twenty seconds, taking six 
movements. Taking an approximate average the scallop would be able 
to cover 1 inch in two minutes, or thirty times its length, if it traveled 
consecutively. 

The crawling stage can be divided into three periods: (1) swimming 



56 THE SCALLOP FISHERY 

and craMding- by means of the foot with its ciliated tip; (2) the true 
crawling stage, where locomotion is by means of the foot; this is found 
only in the early dissoconch scallop and is of short duration; (3) crawl- 
ing with the foot and swimming by a clapping of the valves, as in the 
adult. The actual use of the foot for crawling covers a long period, 
as the animal continues to creep more or less until it reaches a size of 
1%. inches, when the foot becomes too small for this purpose. 

Climhing. — Climbing rather than horizontal crawling seems to be 
the natural instinct of the young scallop, which seems to prefer going 
up the sides of an aquarium to crawling over the bottom. Young seal- 
lops 0.6 to 0.8 of a millimeter, placed in a glass dish, climb up the sides 
until they find a place for attachment by the byssus, crawhng over or 
around obstacles with equal readiness. A needle was placed before a 
crawling scallop, and it climbed up this for several millimeters before it 
found a resting place. The usual point of attachment is just below the 
surface, but the scallop may encase itself in a drop of water somewhat 
above this level. The scallops do not climb out of the water, as evi- 
dently the siphon helps the foot in the work of climbing and it is 
imjDOssible for the animals to lift the increased weight of the body. 

Scallops do not progress with such rapidity as in crawling, as the 
animal is forced to support its weight when making each extension 
of the foot. In the larger scallops the action of the foot is aided 
by the tentacles, which at times seem to offer support as the animal 
rests against the sides of the glass dish. The pseudo-siphon on the 
posterior side of the mantle aids by forcing a jet of water from the 
shell at the same time that the foot contracts. Evidently the scallop 
maintains its position for the most part by means of the foot, which 
makes a double bend so that a second part near the byssal gland touches 
the surface. Possibly by using this portion as an elbow, in the same 
manner as when the byssus is formed, it is able to cling to the support. 
Ordinarily the lift comes directly upon the end of the foot, as scallops 
have been observed hanging on the sides of the dish by merely the tip, 
and to pull themselves up by the contraction of the foot alone. Part 
of the contracted foot then rests on the glass, and the distal end lengthens 
out, searching for another resting place. 

It was observed that 25-milJimeter (1-inch) scallops could climb 
for a distance of 4 to 5 inches on a smooth, perpendicular surface. The 
larger scallops were not so active as the smaller, and the 25-millimeter 
size seems to mark the end of the climbing activity of the animal, the 
foot evidently being unable to support the heavier body. 

The use of the climbing power is connected with the attachment of 
the scallop. Whenever the animal is shaken from its point of location 
it can climb back to another perch on the eel grass. There seems no 
selection in the climbing instinct, only a tendency to mount upwards. 
It is also possible, when the set strikes the eel grass, that the scallops 



OF MASSACHUSETTS. 57 

may have to climb to get their proper positions. If it were not for 
the ability to climb upon the eel grass again, many detached scallops 
would undoubtedly perish. 

Turning Over.- — -The young scallop (Figs. 49-51) possesses several 
resources by which it may orient itself when placed on its upper valve. 
There are two general means, one by help of the foot and the other by 
the clapping of the valves. With the small scallop the use of the worm- 
like foot is the primitive method of getting into a natural position. 
When scallops from 1 to IV2 millimeters are placed on their left valve, 
they at first appear uneasy. After a few moments the animal thrusts 
out its foot, waves it around as if seeking a foothold, and finally ap- 
plies the cleft tip to the bottom of the glass dish with a twisting motion. 
By this movement the shell is pulled so that the hinge line is resting 
on the bottom of the dish (Fig. 50), and the scallop pries itself over in 
the opposite direction, naturally falling into its right position. This 
operation is frequently aided by a slight opening and shutting of the 
valves. The quickest way of turning over in case of the older scallops 
is by clapping the valves, which flips the animal from one side to the 
other. The animal may turn in a lateral direction on the hinge, but 
the usual turn is anterior or posterior, either toward the foot or away 
from it. Another means is to swim with foot extended, usually landing 
proper side up. 

Rate of Traveling. — Observations were made on the rate of travel- 
ing of 3-millimeter scallops, placed both on the right and left valves. 
Scallop A, resting in an unnatural position on the upper (left) valve, 
compared with scallop B, resting on the lower valve, did not exhibit 
as gTeat speed or travel so great a distance. Although young scallops 
do not seem to be as uncomfortable as the old when placed on the 
left side, they do not move so rapidly as in a natural position. Out 
of 19 consecutive moves scallop B showed 11 greater and 7 less than 
scallop A, while one was the same distance. Scallop A traveled a 
total distance of 190 millimeters in thirty minutes, but actually gained 
only 37 millimeters, owing to its random movements. The same ir- 
regularity, in spite of its greater speed, which is aceoimted for by the 
foot having a more direct line of tension for the single left retractor 
when the animal lies on the right side, was noticed on scallop B. The 
animals may move for some time without going far, and may even 
return to the exact place of starting. The distribution of scallops at 
this age is probably determined more by wind and current than by any 
movements of the animal itself. 

Swimming. — The first attempt at swimming occurs when the sur- 
face cells of the scallop embryo acquire cilia. The succession of rotary, 
circular and straight line movements of the larva have already been 
described for this period, and likewise for the early veliger, with 
its ciliated velum or swimming organ. Also, the change from the 



58 THE SCALLOP FISHERY 

swimming veliger to the larva which swims by a kicking motion of the 
foot has been given in chapter III. 

The adult swimming characteristics appear at the beginning of the 
plicated stage, after the mantle has become specialized. During and 
just previous the scallop has passed through a stage in the evolution 
of swimming, which, though closely associated with crawling, is the 
bond that shows its relationship with other lamellibranchs, such as 
the clam and quahaug. It is the " pseudo-siphon stage," so named from 
an organ formed by the edge of the mantle on the posterior side of the 
animal. In crawling, water is ejected from this opening with sufficient 
force to throw the animal ahead. It is interesting to note that this 
movement is the first indication of swimming in the animal, and that 
it is comparable to similar conditions in the other shellfish, which have 
fully formed siphons in the adult. The description of the adaptability 
of the anatomical parts of Pecten tennicostatus (Mighels) for swim- 
ming, as given by Drew (1), applies equally well to Pecten irradians, 
and is here quoted : — 

Pecten is one of the ablest swimmers among lamellibranchs. The whole 
structure of the animal is modified for this purpose. The valves have be- 
come rounded in outline, flattened and comparatively light. The anterior 
adductor muscle has been lost, and the posterior adductor muscle, which is 
very powerful, is situated near the middle of the body. The cartilage has 
become well developed, so the shell may be opened quickly when the muscle 
relaxes, and the hinge line is straight, so there may be no unnecessary 
strains in opening and closing the shell. Each gill is attached by one 
lamella only, so water in the temporary cloacal chamber may be thrown out 
without injuring the gills, and the gills and margins of the mantle are 
provided with muscles to withdraw them from the margins of the shell 
when the shell is closed. Furthermore, the margins of the mantle are pro- 
vided with infolded ridges and with circular muscles, so it is possible to 
direct the current of water which issues from the shell in the required direc- 
tion. 

The only striking difference in the swimming of the young plicated 
scallop and the adult is the extension of the foot by the former, possibly 
a characteristic retained from the old method of swimming with the 
foot. In all the swimming of the young the foot is thrust out to its 
full extent, and possibly assists the animal through the water, either 
by its waving motion or by its cilia. 

The following excellent account of the method of swimming of the 
adult Pecten is given by Jackson (4) : — 

It is best to study the swimming in young Pectens some 3 centimeters 
high, as at that age it is more easily seen than in adults, and does not 
differ from what may be observed in them. Lying on the bottom, with 
tentacles extended, the scallop suddenly folds the guard tentacles back so 
that they lie closely against the outer border of the perpendicular mantle 



OF MASSACHUSETTS. 59 

wall. The valves are then closed by a quick action of the adductor muscle 
and water is forcibly expelled. The first water expelled is driven out pos- 
teriorly in the direction of the arrow A (Fig. 61), and if this were the only 
or the main direction in which a current is expelled the animal would by 
impact of water be impelled in the opposite direction or anteriorly; but the 
action of swimming is more complicated than this would indicate. When 
the valves have closed to a slight extent the borders of the two thick, per- 
pendicular mantle walls come in contact and then no more water passes 
out as indicated by arrow A, but instead, during further closure of the 
valves, it is forcibly ejected from the lower border of one ear, where the 
mantle wall is low and thin, as indicated by the arrow B (Fig. 61). 

The water expelled at the point B is the most forceful current and 
probably of the greatest volume; by its means the creature is impelled in 
the direction of the arrow C. The valves open quickly and clap again. The 
second time, as before, the first water is driven out posteriorly; but when 
the mantle walls come in contact, the direction of the excurrent water is 
again changed, and is forced out from the lower border of one ear, in the 
direction of the arrow D (Fig. 62) ; being the strongest current, it impels 
the animal in the direction of the arrow E. This striking difference is 
noted, viz., that at successive claps the water is driven out from alternate 
ears, first on one side and then on the other. The resultant action of the 
several currents and successive claps, illustrated in Figs. 61, 62, is, therefore, 
to drive the animal in the direction of the free borders of the valves, or 
posteriorly. It is due to the alternate expulsion of the water first from 
one ear and then from the other, as described, that the animal presents a 
succession of zigzag jerks in swimming. The direction of the current 
alternately to the two ears appears to be voluntary, as scallops can scuttle 
over the bottom of a dish in a sidelong direction by successively expelling 
the water at each clap from one and the same ear. The action of the first 
current of water expelled posteriorly, before the mantle walls come in contact, 
gives the animal an upward jerk, and it is in virtue of this jerk, combined 
with the momentum in a posterior direction, that it maintains its position 
on the surface of the water, and also the high angle to the surface which 
it presents in swimming. The current driven out posteriorly in the initial 
closure of the valves is so powerful that water may be squirted by adults 
to the height of five inches or more from the surface by this action. 

A few additional observations upon tlie swimming habit may not be 
out of place. Scallops acquire the power of swimming at an early age, 
as they are able to swim in the manner described above soon after they 
attain 1 millimeter in size. The swimming habit is adopted when the 
scallop becomes less ]Drofieient in moving with the foot, owing to the 
increasing weight of its, body. 

Scallops- are capable of movements in other directions than described 
in the above paragraph. Specimens 8 to 10 millimeters in size, 
when approached ventrally with the point of a pencil, snap their valves 
together and dart back in a dorsal direction, evidently to get away from 
the pencil, which they allow to get within reach of their tentacles before 
moving. The water is expelled Avith a quick squirt from the ventral 



60 THE SCALLOP FISHERY 

l^ortion of the valves. The distance covered on the back dart was about 
10 millimeters. This observation was made several times on different 
scallops, and is interesting, as it shows that the scallop can force water 
from different parts of its shell, in this case exactly at right angles to 
its usual direction. Darts can likewise be made in either an anterior 
or a posterior direction, showing that the body can be forced in any 
desired course by changing the point of expulsion of water from the 
shell. This habit is of a protective benefit to the animal, as the ordinary 
method of locomotion would be such as to carry it to an advancing 
enemy rather than allow its escape by a backward " shoot." This 
method is closely associated with the tactile functions of the tentacles, 
and it is only when stimulated that the scallop makes use of it. 

Eesting. 

The young scallops as well as the old have periods of rest, during 
which they probably feed or merely lie inactive. There are three kinds 
of rest: (1) the scallop attached by the byssus; (2) lying unattached on 
the bottom; (3) floating on the surface of the water. 

Attachment. -^ This position has been defined under " Byssal At- 
tachment," and only the appearance of the scallop needs description. 
The animal is probably in a feeding position, the mantle with its tenta- 
cles is extended, the heart beats slowly, and the food particles rotate 
in the digestive tract. In this position the animal is keenly sensitive 
to stimuli and if touched closes its valves at once. 

Resting on the Bottom. — During the intervals of crawling the young 
scallops often rest on the bottom for a long time. Even in this resting 
position part of the internal anatomy is constantly moving. The cilia 
in the gills, in the digestive tract and on the foot are always lashing, 
while the foot is often restless and Avrithes within the shell. The tenta- 
cles are generally extended and the shell gapes slightly open. The heart 
action is less rapid than in craAvling and at certain times seems to have 
ceased. 

The natural resting position of the adult scallop is on the right valve 
on the bottom. Very seldom, and then only owing to accidental over- 
turning, does it rest on the left valve. Often on a coarse sand bottom, 
especially in winter, the scallop excavates a shallow hole in the sand 
and lies passive, half concealed in its burrow. This habit may be pro- 
tective in severe winters. 

Drifting. — Scallops frequently drift just below the surface of the 
water, with the right valve uppei'most, some with shells nearly closed, 
others with tentacles and foot extended (Fig. 47). The foot evidently 
needs to gTasp some object before the animal can control the direction 
of the motion. If one of the drifting animals is jostled with a needle 
it sinks to the bottom, probably taking in a little water. Scallops as 



OF MASSACHUSETTS. 61 

large as 10 millimeters have this habit of floating, and scallops of 6 
millimeters are often found with tentacles widely spread out. The 
reverse position of the animal, the right or lower valve being uppermost, 
is not so unnatural as may seem at first, as it can be lil?;ened to the crawl- 
ing of a fly on the ceiling. The surface of the water acts as a wall 
upon which the scallop, with its extended foot, can rest. Pecten and 
Anomia have been observed apparently crawling, right valve up, on the 
surface of the water in the same manner as on the bottom, only in a 
reversed position, evidently in a similar manner to snails, by mucous 
secretion. 

In the ease of the small scallops, the tentacles, which appear to sup- 
port the larger scallops, are not essential for floating. Very small disso- 
conch scallops, before the formation of tentacles, have the floating 
habit, and do not depend, therefore, on the tentacles to support them. 
The habit of floating is useful in that it probably allows the scallop 
the opportunity to get a better supply of oxygen, and to be carried from 
one locality to another or from one stalk of eel gi'ass to the next by the 
current. 

MlGRxiTION^. 

Many remarkable stories concerning the movement and migratory 
habits of the common shallow-water scallop have long circulated among 
the fishermen. Several writers have described schools of scallops in 
the act of skipping and swimming over the surface of the water, and 
have attributed to this species the migratory powers of fish. Scallops 
are reported to traverse many miles, passing from one part of the coast 
to another, continually on the move. Unfortunately, these stories have 
arisen from incomplete observations, which, supplemented by the use 
of the imagination, have credited the scallop with powers it never 
possessed. Indeed, so much has been said concerning the swimming 
powers of the scallop that people have come to believe that the scallop 
should be considered as a migratory fish. 

While the basis of these reports is correct, there has been much 
exaggeration. The scallop has the power of migration only in a limited 
sense, and although capable of swimming never traverses far. In a 
small bay or harbor it is possible for the scallop to move to various 
parts, especially if there is a strong current, but extended and definite 
movements never occur. Swimming is a frequent diversion of the scal- 
lop, which, after lying quietly on the bottom, suddenly takes a slanting 
" shoot " through the water. The scallop is not built for continuous 
traveling, as it seems to need periods of rest between each flight. The 
average distance covered in a single movement is about 10 feet, while 
often it is much less. The longest flight ever noticed by the writer 
was about 25 feet, which is an exceptionally long distance for the 
scallop to traverse at one time. Occasionally a series follow in quick 



62 THE SCALLOP FISHERY 

succession, but more often many hours elapse between them. As the 
scallop is incapable of making continued flights for any distance its 
migratory movements, if such it has, are limited to certain definite 
areas, and never extend over a large territory. 

A swimming habit of the scallop, which undoubtedly gave rise to 
the mistaken idea that they swam in schools on the surface of the 
water, can be observed particularly toward evening, when the scallops 
in the shallow water rise to the surface, shoot a jet of water in the air, 
and then, closing their shells, sink to the bottom. This fact has given 
rise to another popular fallacy, that the scallop has to come to the sur- 
face to breathe. The real explanation of this peculiar habit lies in the 
swimming of the scallop. In swimming water is taken in by opening 
the valves, and is then ejected on either side of the hinge line. The 
scallop, in traveling through the water, is forced to take an upward 
slant to keep moving, and in shallow water the animal soon rises to 
the surface. Not being able to take in any more water by opening its 
valves, the animal gives one final squirt, and sinks to the bottom with 
closed shell. This strange habit of the scallop is readily explained as 
the natural result of the sudden ending of its swimming. 

The idea that the scallop makes a definite migration from shallow 
to deep water during the warm months of the summer, and returns to 
the shallow water in the fall, has spread widely. Where this idea 
could have arisen is impossible to state, but it has always been con- 
sidered as an established fact. As far as could be discovered by the 
experiments and observations, the idea is wholly erroneous. Scallops 
have never been seen to make any such definite migTation during the 
summer, and monthly records have been kept of scallops in the shallow 
water in as many as fifteen localities in the State, with the result that 
no movement of any kind was observed during the whole season. Not 
only were observations made for one year, but for a period of three 
consecutive years, which seems to conclusively indicate that no such 
migration ever takes place. 

There are several possibilities for the irregular movements of the 
scallop, and the element of chance has a great deal to do with its travel- 
ing. If a bed of scallops happens to be in a swift current the scallops 
may be carried along by the strength of the current, whenever the 
animals rise in the water. As this is usually a tidal current the dis- 
tance traveled is not far, and the opposite tide washes them back to 
the starting place. The scallops in a heavy wind are rolled along the 
bottom and in this manner are carried some distance. This method 
of migration likewise depends on chance, and is only applicable to 
scallops in shallow water, where they are unprotected by eel grass. 
Many scallops are yearly washed ashore, which is sure indication of 
the force of the waves ^nd helplessness of this bivalve. Undoubtedly 
this is the most extensive means of traveling, and is probably the only 



OF MASSACHUSETTS. 63 

one of importance. A third method of migration is possible when the 
young scallops are attached to eel grass by slender byssal threads. 
When the eel grass is torn ujd the young scallops drift with the wind 
and tide for long distances. In this way localities that have not had 
scallops for years can again be restocked, Ingersoll (8). 

The scallop is short lived, very few ever reaching the two-year limit. 
The majority, therefore, have only one spawning season. If any 
adverse natural condition, such as a severe winter, kills off the smiall 
" seed " scallops for that year, the total crop for the following year 
will be exterminated, as it is a ease where there is only one set of scal- 
lops spawning at a time, and generations so follow generations that all 
the scallops which are to furnish the spawn belong to the same set. 
In this way the scallop crop of any locality is often wholly extermi- 
nated, and it takes years before it can again assume its former propor- 
tions. Thus the uncertainty of the scallop crop makes it appear that 
the scallops migrate from one town to another, as one town will have 
an abundance one year, perhaps followed by a poor season, while the 
reverse may be true for neighboring towns. So what has apparently 
been considered a migration is in reality no migration at all, but is 
merely due to the short life of this interesting mollusk. 

There are several facts that substantiate the non-migration of the 
scallop. While none can be termed actual proof, nevertheless they 
furnish strong evidence that the scallop as a rule does not travel far 
from its native place. It was found almost impossible to obtain definite 
data on the movement of the scallops, as there was no accurate way in 
which to observe them in their native haunts. One attempt was made 
which gave results of negative quality. About 400 tagged scallops were 
liberated in Nantucket harbor in such a location that they would have 
to cross the channel to get to the scalloping grounds. The scallops were 
tagged with copper wire through the " ear " of the shell, which did not 
hinder to any extent their movement, and were liberated in October, at 
the beginning of the scallop season. Careful watch was kept by the 
scallopers on the fishing grounds, but none were ever found, indicating 
that they had not traveled. They were so located that the least traveling 
would have carried them to some part of the scalloping territory. 
The possible errors were: too few scallops, interference of the tags 
with the traveling and the possibility that they were carried to other 
places than the scalloping grounds, or that they were overlooked by 
the scallopers. 

While there is much difference of opinion among the fishermen as 
to the movement of the scallop, the majority believe that there is little 
or no traveling, basing their claim on the fact that they find scallops 
in the same place the year round, and that the beds shift but little. ISTew 
beds seem to spring up when the eel grass is roUed away, but the 
scallops probably have been there always, or have been carried a short 



64 THE SCALLOP FISHERY 

distance by either wind or tide, and have not come from miles away, as 
has been frequently supposed. 

In all the observations made by the Massachusetts Depai'tment of 
Fisheries and Game on the habits of the scallop records have been kept 
of the different sets in many scalloping localities in the State, and no 
case of extended migTation has been recorded. It has been impossible 
to make as extended observations in the deep water as in the shallow, 
but there is every reason to believe that the same conditions hold true, 
in spite of the fact that the scallops can more frequently be carried by 
the current. 

A further fact of interest in this connection is the distinction between 
the two sizes of scallops, the large channel or deep-water scallop, and 
the small shallow-water or eel-gTass variety. These two are the same 
species, but, owing to the better growing conditions in the deep water, 
the channel sealloj> is much larger in size. If the scallop were a migra- 
tory form, and would travel first to deep water and then to shallow, 
there would be no well-marked distinction between these two groups, as 
all scallops would be approximately the same size. This fact furnishes 
excellent proof that there is no such, thing as definite migTation. 

In conclusion, the matter can best be summarized by stating that while 
the scallojD is capable of swimming through the water by its own exer- 
tions, it can never travel any great distance in this way, and that there 
is no such thing as definite voluntary migrations. While no exact proof 
can be obtained there is not sufficient evidence to show that the scallop 
ever travels, and the weight of the evidence implies that there is never 
any migration. The only possible traveling of the scallop is caused by 
forces external to the animal, such as wind, current, storms, etc., and is 
merely a matter of chance. This cannot be styled in any sense a true 
migration, and there is little evidence to show that any considerable 
distance is traveled by this means. 

The non-migTatory habit of the scallop is of importance to the scallop 
planter if in the course of future events cultural methods are ever 
applied. It is also of great importance to the town, as no town may 
feel that their scallop crop will travel to the borders of the neighboring 
township. The scalloping towns can rest assured that, if the scallop 
crop is once within their borders, there is slight chance that it will 
ever leave. 

Recovery from Injury. 

Scalloi^s are frequently found with twisted and warj)ed shells, or 
other deformities. Jackson (4) reports finding scallops with portions 
of the mantle missing, evidently from the attacks of predacious fish. 
Occasionally small fish about 1 inch in length are found within the 
scallop shell. In many of the gTowth experiments, where the scallops 
Avere kept in confinement in wire baskets, the growth was abnormal, as 
the shell grew in a variety of shapes, owing to the manner of resting 



OF MASSACHUSETTS. 65 

against the wire. To observe their recovery from injury, scallops were 
treated in a variety of ways: (1) four scallops were unhinged by break- 
ing the ligament; in three days' time three were dead, one was alive ; 
(2) small holes were bored in shells of three scallops: all were dead in 
three daj'^s; (3) five with adductor muscle badly strained: in three days 
two were dead, three alive; (4) three with valves cracked lengthwise: 
in three days one was alive, two were dead; (5) one with valve cracked 
along byssal groove: alive two weeks later but shell not mended; (6) 
three with small piece cut out of mantle edge; in three days two were 
alive, one was dead. The result of these mutilations shows that the 
scallop, although not as hardy as the clam or quahaug, is capable of 
repairing minor injuries inflicted by enemies, and only succumbs to the 
more severe hurts. 

Feeding Habits. 

The feeding habits of the scallop are similar in many respects to those 
of the other shellfish, as all lamellibranchs obtain their food by means 
of the gills, which act as filters or strainers. The clam and quahaug lie 
beneath the surface of the soil and reach the water by a fleshy extension 
of the mantle, known as the siphon. The scallop has no siphon and its 
method of life is such that it does not need an organ of this nature. 
When in a natural jDOsition for feeding, the animal rests on the bottom 
on its right valve, the shell gaping open at an angle of about 20°. 
Closely lining the inside of the two valves is a thin fleshy substance, the 
mantle, described in chapter II. When extended, the edge, lined with 
papillose tentacles and brightly colored eyes, passes beyond the shell, 
while another portion, consisting of a perpendicular flap, surmounted 
with a row of closely set guard tentacles, acts as a curtain to nearly 
close the intervening space between the open valves. Instead of the 
specialized siphon of the clam, which is in reality only a part of the 
mantle, the scallop makes use of the entire ventral area of this fold to 
take in its food, with the result that a continual stream is passing in 
through the mantle and going out at a definite locality in the posterior 
side of the shell. This portion of the mantle is destitute of guard 
tentacles, and, when the walls are closed together, forms a pseudo- 
siphon. 

The food of the animal, as more fully described in the report on the 
food of the lamellibranchiate mollusks, consists largely of certain micro- 
scopic plants, called diatoms. These tiny forms are extremely varied in 
size and shape. They are easily recognized by their silicious eases and 
beautiful markings, which have won for them the name of " the jewels 
of the plant world." They are found in the water everywhere in more 
or less abundance, and are filtered out by the scallop from the water 
which bathes its gills. 

The four gills, which were described in chapter II., in addition to 
aeration of the blood possess the important function of straining food 



66 THE SCALLOP FISHERY 

from the water. Lying free in the body cavity, they are constantly 
surrounded by the flowing Avater, which passes through and around the 
filamentous bars. When examined under a microscope the gills are 
found to be covered by small hair-like cilia, lashing in a definite direc- 
tion. These cilia cause currents of water to pass over and through the 
gills, while other cilia between the filaments act as minute sieves to 
strain out the food particles, which are at once cemented together with 
a mucus and propelled by the ciliary action toward the popularly 
called " backbone " of the gills, or the dorsal edge. Here they are taken 
up in a more definite channel and swept with increasing velocity toward 
the upper end of the gills to the lower edges of the palps. The palps 
are ridged and furrowed like the gills, and the food is transferred to 
the mouth by means of these " lips." If an excess of food or foreign 
matter is caught by the gills, the animal, by a complicated mechanism, 
as described by Kellogg (3), is able to cast it off. 

The effete matter from the digestive tract is carried out from the 
shell at the posterior j)seudo-siphon. The waste in transverse section 
has the appearance of a three-leafed clover, Jackson (4), and is of 
uniform length. When the scallop lies feeding in the aquarium, the 
feces pass out at regular intervals of about a minute, suggesting a 
nearly constant need of food. The constant flow of water through the 
shell shows that the other parts, such as mantle, visceral mass, etc., must 
likewise be ciliated as well as the gills, in order to force the flow of 
water in one direction, an entirely different arrangement from the 
ejection of water by the mantle in swimming. 

Sensory Powers. 

The exact reactions of the scallop to light and other external stimuli 
have never been worked out, and there remains a wide field for investi- 
gation on these points, especially in regard to the effect of light. The 
following are a few meager observations which it is hoped may interest 
some one to take up the study of the sensory powers of the scallop. 

The scallop is sensitive to a sharp tap or sudden jar. When small 
6-millimeter scallops are attached to the sides of glass dishes, the valves 
remain open, tentacles extended. A sharp tap on the outside of the jar 
directly over the animal causes it to retract its tentacles, but after 
repeated tapping the creature does not seem in the least disturbed, as 
the tentacles remain extended. All motions outside the glass dish were 
unnoticed by the scallop. 

At times the adult scallop is quite sensitive; again, the same stimulus 
does not excite the animal. Evidently it has various moods. Jack- 
son (4) states that when spinning the byssus the scallop appears undis- 
turbed by pricks, etc. As cold weather comes on the animal becomes 
less active and fails to respond with its former alertness. 

The eyesight of the animal has aroused considerable comment. The 



OF MASSACHUSETTS. 67 

eyes, so far as concerns the gross anatomy, closely resemble those of the 
higher animals, and are connected to the eircumpallial nerve by short 
nerve fibers. To what extent the animal can see is a question. Observ- 
ers have stated that scallops lying on the eel grass notice a person 
wading through the water and swim off. Whether this is due to sight 
or to the disturbance of the water is uncertain. It is true that move- 
ments in the water have more effect than those outside, and the effect of 
shadows on the scallop may cause it to withdraw its tentacles. The 
approach of enemies is readily recognized by the scallop, which scuttles 
out of harm's way. Whether this is from sight or other modes of sensa- 
tion is as yet undetermined. 

Veliger scallops apparently are not sensitive either to dark or light. 
With scallops of 2 millimeters and over, in which the eyes or tentacles 
are developed, different results were obtained. A few tests were made 
with animals of this size in small dishes, covered with black paper, 
except in certain places for the admission of light at the will of the 
operator. Many of the results were negative, but a slight heliotropie 
(toward light) tendency was evidenced. 

The young scallop under 3 millimeters evidences little preference for 
different colors. Tests along this line have given negative results, as 
the distribution on areas of different color seemed at random. 

Scallops will live in waters that have a density of 1.010 or greater, 
one-half salt to one-half fresh. This has been tested by observations in 
difl'erent locaHties and by keeping the animals in aquaria with various 
densities. .The scallop, compared with the clam and quahaug, succumbs 
more readily. In aquaria, where these burrowing moUusks will live 
indefinitely, it is often difficult even with running water to keep the 
scallop alive for more than two to three weeks. 

Enemies. 

Owing to its free life and activity the scallop is beset by relatively few ■ 
enemies, as compared with the oyster, or, more properly speaking, 
suffers less destruction from the same adversaries. Nevertheless, there 
are certain species which prove dangerous and cause the scallop a con- 
tinual struggle to maintain its existence. Naturally in the early life 
of the scallop the destruction is much greater, and it is necessary to 
divide the enemies of the animal into two classes : those which menace 
(1) early life; (2) adult. 

Enemies of the Young Scallop. — In the early Hfe of the young scallop 
it is not so much the active animal enemies as the adverse natural 
conditions that destroy the embryonic larvae. When the fact that only 
one of the several million eggs liberated by the adult spawning scallop 
ever reaches maturity is considered, the extent of the destructive powers 
of nature becomes strikingly manifest. The early life of the animal is 
the critical period of its existence, and it is at this point that the young 



68 THE SCALLOP FISHERY 

must be shielded from their enemies. The active enemies of the young 
larvae can be enumerated: fish, other shellfish and animals of similar 
nature which suck down the larva for food, the adult scallop often 
treating her young in this manner. Later in life, when the young 
scallop is discernible to the naked eye, the starfish, crabs, sea fowl and 
other predacious animals feed upon it. Scallops of nearly II/2 inches 
in size have been taken from the crop of an eider duck by John H. 
Hardy, Jr., of Chatham. 

But the force which causes the vast destruction is not accounted for 
by these active enemies. It is broader and farther reaching in its in- 
fluence. It is nature, with her vast adverse conditions. Severe weather, 
storms, sudden changes in temperature and in salinity of the water 
during the spawning season, sewage and other contamination, may 
bring about the destruction of the floating larvae. The localities of set 
are such that only a limited area is available for the retention of the 
spat. Eel-grass-covered flats are best adapted for the set, and other 
localities generally prove unfruitful. The larvae, uniformly scattered 
through the water, are washed hither and thither, relatively few ever 
setting on good ground, the rest either washing ashore or being buried 
on slimy and unwholesome bottom. Thus the infant mortality is es- 
pecially great and only a very few escape the perils of the embryonic 
stage of their existence. These few are now at the mercy of the 
elements until they have attained sufficient size to enable them to take 
care of themselves. On the eel gTass they are constantly in the danger 
of washing ashore. When the set is on shallow flats, for example, 
the Common Flats of Chatham, the scallops are nearly exposed at low 
running tides, and thus often are killed by the severe winter frosts and 
ice. Even when in deeper water, the " anchor frost " is said to destroy 
them in great numbers, but fortunately this condition is rarely found. 

Enemies of the Adult. — The adult scallop has several natural ene- 
mies, including man, both active and passive, as well as being subject 
to the adversities of nature, for the scallop, by reason of its specialized 
anatomy, is most susceptible of all economic mollusks and readily suc- 
cumbs to an unfavorable environment. 

(a) The Starfish. — The starfish {Asterias forhesii) is probably the 
most destructive pest of the scallop fishery, and has proved a source 
of great annoyance and loss to the scallopers. Fortunately the inroads 
of this pest are chiefly confined to one section of the State, Buzzard's 
Bay, and although the animal is found in some abundance along the 
south side of Cape Cod and at the islands of Nantucket and Martha's 
Vineyard, it is not so serious a menace to the industry. Many of the 
Buzzard's Bay fishermen attribute the decline of the scallop fishery 
in those waters some eight years ago to the invasion of the great num- 
bers of starfish at that time. From reports by the fishermen the scallop- 
ing grounds were literally paved with starfish, and it was utterly 



OF MASSACHUSETTS. 69 

impossible for the scallops to escape destruction. It is well known 
how destructive the starfish is to the oyster beds, and undoubtedly the 
scallops would not be able to escape so great a number and must have 
suffered severely. Capt. James Monahan of Wareham cites the follow- 
ing instance : " In the fall of 1898 I located a bed of seed scallops 
so thick that half a dredge full could be obtained at a single drift. 
Next year I went to the same place, and on casting my dredges found 
them full of dead scallops, shells and starfish in great number." He 
estimated that in that one locality 1,000 bushels perished. 

During the season of 1907-08 nearly every boat from Wareham 
saved the starfish, and instead of throwing them overboard, as was 
previously the custom, carried large numbers to the shore. Under the 
old method of carelessly returning these pests to the waters they were 
scattered over a wider area from the boats. For two seasons previous 
to 1907-08 it is said that the starfish had been decreasing, and that the 
return of the scallop fishery after an absence of seven years was due 
to this decline. Many seallopers and oystermen are anxious for State 
appropriations for the removal of these pests. 

The method of attacking the scallop (Fig. 70) is similar to that used 
on the oyster, i.e., opening the shell by means of a steady strain exerted 
in opposite directions upon the two valves. The starfish surrounds the 
scallop with its long arms or rays, five in number, and clasps it in its 
embrace, generally in such a way that the mouth of the starfish rests 
just above the byssal notch of the scallop, and the arms are closely 
attached to the shell by the tube feet or suckers. By exerting a steady 
pull with its numerous suckers, and by the tendency to straighten out 
the long arms, the animal exerts a strong and steady strain on the 
adductor muscle, which, though well adapted to resist a sudden pull, 
gradually tires and relaxes. The starfish has the advantage, as, having 
five arms, it can rest some of them and yet keep on pulling, while the 
scallop has only one muscle and has to exert a perpetual strain. Then 
a curious phenomenon is noticed. The starfish rolls out its stomach 
and allows it to flow into the interior of the scallop, where it digests, 
outside its own body, the soft parts of the scallop. When the meal is 
completed the stomach is withdrawn, and the clean scallop shell left 
with gaping valves. 

Small starfish seem to be the most active in this work of destruction, 
and the " seed " scallops are the most frequent objects of their attack. 
The only method of reducing this pest, as extermination is practically 
impossible, is for the seallopers to carry the starfish taken in dredging 
to the shore. The oystermen, who suffer more severely from the inroads 
of the starfish, most commonly use a tangle or mop which is dragged 
over the oyster beds, the " five finger " becoming easily entangled. The 
starfish are then either thrown into boiling water or carried ashore. 

(&) The Oyster Drill. — Where the scallop is not found the oyster 



70 THE SCALLOP FISHERY 

drill (Urosalpinx cinerea) (Fig. 68) is generally present. This little 
gasteropod mollusk, nest to the starfish, is the most destructive enemy 
of the scallop and oyster, and is found in nearly every scalloping lo- 
cality. Scarcely more than an inch in height and of an innocent grey 
color it has proved a source of trouble to the oysterman, owing to the 
impossibility of thoroughly removing it from the oyster beds. 

Its method of attack is to crawl upon the upper valve of the scallop 
and then pierce a hole in the thin shell, scarcely larger in diameter 
than a needle, by means of a tiny ribbon-like tongue armed with fine 
teeth. When the boring is completed the animal sucks out the contents 
of the shell. Scallops have been found destroyed by the drill bearing 
on the shell a row of globular egg eases which the drill had deposited. 
It is during this process that the scallop has an advantage over the 
oyster. The latter is fixed and immovable, the former is capable of 
movement, and by a few well-directed flaps of the shell can in many 
instances throw off the intruder and escape destruction. The numerous 
half punctures in many living scallops bear witness to the inability of 
the " borer " to finish its task. 

A few observations upon the length of time it takes to bore and eat 
a scallop were made at Monomoy Point with a view of determining the 
actual extent of destruction. Scallops were confined with the drills 
in boxes with netting tops. Different numbers of scallops and drills 
were used for over a month. As many as five drills have been found 
on one scallop not in confinement, and as many as two or three are of 
common occurrence (Fig. 95). The conclusion arrived at from these 
observations was that it took from four to six days for the drill to 
pierce the shell sufficiently to eat the contents, and that the meal was 
consumed in about the same amount of time. At this rate the drill 
could only eat about three large scallops per month, even if nothing 
interfered with the operation, and in the long run the amount of 
destruction would be extremely slight. While the unnatural condition 
of the confined animals may have made the process slow, the limited 
area afforded the scallop but slight chance to escape from its enemy 
and so partially offsets any error. 

(c) Nassa obsoleta. — The third active enemy of the scallop is per- 
haps hardly to be classed under that head. It is the scavenger of the 
tidal flats, the little black winkel, Nassa obsoleta, which has the im- 
portant duty of cleaning the flats. The actual damage done by this 
animal is comparatively small, as it is not an inhabitant of the same 
localities as the scallop as a rule, being found between the tide lines. 
Nassa is commonly thought to be of little damage to living shellfish, 
though it is known to eagerly devour any dead or broken specimens. 
Although the damage is of little account the method of attack is so 
interesting that it will bear relating. The scallop when resting on the 
bottom with tentacles extended is at times extremely sensitive, and then 



OF MASSACHUSETTS. 71 

again less so. Nassa possesses an extremely well-developed sense for 
finding food and gathers around the scallop in numbers. Then a con- 
certed action takes place, whether intentional or by accident, but it 
occurs time and time again. One Nassa forces itself between the valves 
of the unwary scallop, which at once close with a snap, but only part 
way, as the little winkel has formed a wedge between the valves which 
permits the entrance of more of its kind, which rapidly fall to eating 
the contents (Fig. 94). While we cannot attribute this mode of 
attack to any reasoning powers of the small creatures, the fact remains 
that 17 out of 500 scallops, confined in a pen 10 feet square, in two 
weeks' time were killed in this way. However, under natural conditions 
this would be impossible in the open. The scallops were observed con- 
tinually to flirt off the crawling Nassa by snapping the valves, and in 
this way were able to protect themselves. 

(d) Passive Enemies. — The scallop has besides these active enemies 
other passive foes which perhaps do not accomplish so much apparent 
damage but affect the growth of the animal and in some eases result 
in its death. Such are the enemies which use the same food and retard 
the growth by depriving the scallop of sufficient nourishment. All 
other shellfish, both valuable and of no importance, come under this 
head. Another class of passive enemies are the ectoparasites on the 
scallop shell, the sea weeds, such as Enteromorpha, Ulva lactuca, etc., 
barnacles, Serpula (worm tubes), Anomia, Crepidula, oysters from 
one to two years old, Acmaea, etc., which not only partake of the same 
food but hinder the movement through the water, and in eases like 
the oyster and serpula, by their growth in time kill the scallop, in the 
case of the former by weight of shell, with the latter by binding edges of 
the valves together. 

(e) Man. — While the main cause of the decline of the natural clam, 
quahaug and oyster beds is overfishing by man, the decline of the scallop 
fishery cannot be so considered. The scaUop has a short life, hardly 
25 per cent, passing the two-year limit; so it does no harm to capture 
the marketable scallops which are over sixteen months old, as the scallop 
spawns when one year old and dies a natural death usually before it 
reaches a second spawning season. When only old scallops are taken, 
as is generally the ease, it is probably impossible for man to exter- 
minate the scallops by overfishing. Unfortunately, in certain localities 
in the past there has been a large capture of the " seed " scallop, viz., 
the scallop less than one year old, which has not spawned. This has 
worked the ruin of the scalloping in these localities. The capture of 
the spawners for another year merely makes the next year's set so 
much smaller, and causes a rapid decline. 

As a rule, it is hardly profitable to catch the " seed " scallop, owing 
to its small size. But a direct relation can be established between a 
high market price and the capture of seed. When the market price is 



72 THE SCALLOP FISHERY 

high aud scallops are scarce, it becomes profitable to catch the young 
" seed." The present scallop law now defines a " seed " scallop and 
forbids its capture. By protecting the " seed " scallop, the State has 
done all that at present appears expedient to insure the future of the 
industry; the rest lies in the hands of the towns. 

So, while the scallop has declined in certain localities, and the decline 
has been hastened by unwise capture of the " seed " scallop, the main 
decline of the fishery cannot be attributed to wholesale overfishing, as 
it is impossible to overfish if only the old scallops (over one year old) 
are taken; for, unlike most other animals, the scallop usually breeds but 
once, and its natural period of life is unusually brief. These scallops, 
if not taken, will die, and prove a total loss; so every fisherman should 
bear in mind that, as long as the " seed " scallops are protected, severe 
fishing of large scallops is not likely to injure the future scallop 
industry. 

The adult scallop has to contend against the same adverse physical 
conditions of nature that beset the young animal. Severe winters, 
storms, anchor frosts, etc., work destruction upon the helpless scallop. 
Exposure to low tides, as on the Common Flats of Chatham, and on the 
north side of Cape Cod; exposure to sewage contamination, as in New 
Bedford harbor; exposure on an open coast, as is occasionally the ease 
on the south side of Cape Cod; sudden changes in the salinity of the 
water, i.e., by flood waters; the distribution of tides and currents; the 
temperature of the water ; the nature of the bottom, — all affect the life 
of this moUusk, and render its existence precarious. 

The very nature of the scallop's period of life renders it peculiarly 
sensitive to adverse conditions, and places difficulties in the way of its 
natural propagation. 

As the scallop dies before reaching its second birthday, only one set 
of scallops spawn in any one season. There are never two generations 
of scallops spawning at one time. I quote from Ingersoll (8) in this 
connection : — 

This represents a case where the generations follow one another so rapidly 
that there are never two ranks, or generations, in condition to reproduce 
their kind at once, except in rare individual instances, since all, or nearly 
all, of the old ones die before the young ones have grown old enough to 
spawn. If such a state of affairs exists, of course any sudden catastrophy, 
such as a great and cold storm during the winter, or the covering of the 
water where they lie for a long period with a sheet of ice, happening to 
kill all the tender young (and old ones, too, often) in a particular dis- 
trict, mil exterminate the breed there; since, even if the older and tougher 
ones survive this shock, they will not live long enough, or, at any rate, 
will be unable to spawn again, and so start a new generation. 

The set of young scallops is abundant in shallow water upon the 
eel-grass flats, which often, as is the case of the Common Flats at Chat- 



OF MASSACHUSETTS. 73 

ham, are exposed at extremely low tides. A severe winter often kills 
0&. all the " seed " thus exposed. In this case no spawn is obtained 
the following summer, causing the suppression of the scallop fishery 
in that locality for at least a few years, and possibly its permanent 
extinction. 

The low temperature during the winter, particularly in the shallow 
waters and on the exposed flats, is often destructive to the adult. Scal- 
lops have been observed in zero weather frozen, with shells full of ice, 
as they lay on the exposed flats at Parker River, Yarmouth. Un- 
doubtedly many die, but many recover from being frozen, as shellfish 
will live if properly thawed out. In the severe winter of 1904-05 the 
entire crop of scallops was killed on the Common Flats, Chatham, and in 
1906-07, 40 per cent, of the ''' seed " on the Stage Harbor flats, Chatham, 
succumbed to the ice and cold. Often the ice settling on the flats 
carries with it the scallops, or leaves them in a djdng condition. Low 
temperatures, tides and currents work together, as the scallop, rendered 
inactive by the coolness of the water, is at the mercy of the elements, 
and is readily washed ashore, to perish on the open beaches or high flats. 

Popular Fallacies. 

Many interesting but erroneous ideas concerning the habits of 
the scallop have arisen among the fishermen, and a brief mention of 
several will bring this chapter to a fitting close. The length of life of 
the scallop has always been a perplexing question. While the majority 
of the scallopers have drawn correct conclusions from their practical 
observations, a few still maintain that this moUusk lives for a long 
period of years. Arguments to this effect are based chiefly upon the 
foreign growth, which is abundant on the shells of the old scallops. 
Successive layers of Crepidula (quarter deckers or sweetmeats) piled 
one on top of the other on the shell are claimed to denote a yearly 
period for each new animal, and large barnacles, worm tubes, etc., are 
considered as indicating a long period of development, while in reality 
these bodies are the result of only a few months' actual growth. 

The idea that it was necessary for the scallop to come at least once 
a day to the surface to breathe arose from seeing the animals rise in 
shallow water to the surface when swimming. Such a conception 
appears absurd when it is known that the scallop possesses gills like a 
fish and is not an air-breathing animal. Numerous misconceptions as to 
its migratory, swimming, attachment, feeding and other habits have 
prevailed during past years, and it is sincerely hoped that this chapter 
on habits may aid in clearing many misunderstandings about the life 
of the scallop. 



74 THE SCALLOP FISHERY 



CHAPTER V. — GROWTH. 

The rate of growth of the scallop, besides being of popular interest 
among the fishermen, has an important bearing on the development of 
the fishery. Owing to its intimate connection with practical scallop 
culture, a detailed study of the rate of growth comprised a large part of 
the investigation. In addition to extending the knowledge of the fisher- 
man and defining the proper relation of growth to protective legislation, 
several facts of biological interest have been brought out by the experi- 
ments, and although not at present of practical importance, they are 
likewise included for the benefit of persons interested in the study of 
the MoUusca. 

In the determination of the average growth of any shellfish it is diffi- 
cult to make definite statements, as the natural conditions, which influ- 
ence development, are varied. The rate of growth for one body of water 
is different from the growth in other localities, unless the same condi- 
tions are present, instances of which occur but rarely in nature. This 
fact not only has rendered difficult the concise presentation of the sub- 
ject, but also has -necessitated a manifold duplication of the experimental 
work in order to satisfactorily cover the conditions in Massachusetts 
waters. Therefore, the reader must understand that the general figures 
given in the following pages do not hold true for individual localities 
and are but the averages for certain sections. 

Methods of Investigation. — The natural conditions of the scallop 
grounds in Massachusetts are dissimilar to the Rhode Island waters, 
Buzzard's Bay being the only section at all approximating the conditions 
in Narragansett Bay. These differences will be brought out later by a 
comparison with the growth experiments of Risser (2) on the Narra- 
gansett Bay scallops. The variety of conditions presented in the differ- 
ent localities of Massachusetts necessitated an extensive series of 
experiments, covering the same ground and in several instances with 
results at variance with the observations of Risser. 

The opportunities for solving the rate of growth of the scallop imder 
a variety of natural conditions were especially favorable owing to the 
diversity of the different scallop grounds. The average rate of growth 
for the different sections in the State, as here presented, is the result 
of three years' continued observations on sets of scallops under various 
environments. Excellent facilities for detailed work on the growth and 
length of life for a period of four years were afforded at Monomoy 
Point in the nearly landlocked harbor, the Powder Hole, and a large 
share of the experimental observations, many of which could never have 
been obtained elsewhere, were made in this locality. Inclosed in a 
natural aquarium, the scallops could be followed from birth to death 
under conditions many of which were under the direct control of the 
operator. 



OF MASSACHUSETTS. 75 

The general work consisted of two parts: (1) at Monomoy Point on 
the scallops confined in the Powder Hole; (2) records of the growth^ 
of the different sets at different localities along the southern coast of 
the Commonwealth. The investigations were first started in July, 1905, 
and continued steadily through 1906 and 1907. Records were also 
maintained in several localities for 1908 and 1909, while the work at 
Monomoy Point was continuous for the whole period. During this 
time records of the complete sets of 1904 (second year), 1905, 1906, 
1907, 1908 were made at Monomoy, and for the State in 1904, 1905 
and 1906. Another division of the work of a different nature can be 
made: (1) experiments in artificial culture, where the scallops were 
confined in pens of wire netting at Monomoy, Marion, Monument Beach 
and Chatham; (2) records of the growth under natural conditions on 
the scallop grounds by measuring large numbers of scallops. A descrip- 
tion of the methods of work, details of measuring, construction of pens, 
marking of scallops, etc., is given in chapter VII. 

General Growth. — The shell or exo-skeleton of the scallop is com- 
monly considered the growing part and any increase in its size indicates 
the development of the animal. New shell formation is the direct 
result of a previous corresponding growth in the soft parts, whereby 
an extension of the shell is necessitated. In the following experiments 
the shell has been considered as typifying the development of the body, 
and all measurements have been recorded on this basis. The quality 
of the meat and the fattening of the tissues, so important to dealer, are 
not considered under the subject of growth, but are discussed in con- 
nection with the " eye " in chapter VI. 

Shell formation by the secretion of the thin mantle lining the inside 
of the shell has been described in chapter II. The shell is built almost 
entirely of lime salts (principally the carbonates), which is obtained in 
some unknown manner from the water. It appears that the amount of 
lime in solution in the water is an important factor in the rapidity of 
growth, but is not as essential as the nourishment of the soft parts by 
the microscopic food. The actual increase in the rate of growth by an 
excess of lime is but slight, as the shell formation naturally depends 
upon the growth of the soft parts, and the difference is only evidenced 
by the increased weight of the shell in localities rich in lime salts. The 
lime supply varies somewhat in the different localities, and its efficiency 
is largely dependent upon the circulation of water. 

In considering the rate of growth the matter of food is of chief im- 
portance. Within limits the growth of any mollusk is directly propor- 
tional to the amount of food it consumes. Scallops situated in good 
feeding localities will grow much faster than those less fortunately 
located. The food as stated in chapter IV. consists of microscopic 
plant forms, called diatoms, which are uniformly distributed through the 
water. Naturally the abundance of diatoms in any locality and the 



76 THE SCALLOP FISHERY 

circulation of water or current are the two external factors in the devel- 
opment of the scallop. 

Growth of Scallop compared with Other Economic Bivalve Mollusks. 
— The limited life and active habits of the scallop require a quick 
maturity and light shell, which make its growth the most rapid of the 
economic bivalves. Arranging these mollusks in order of rapidity of 
growth, scallop, clam, sea clam, oyster and quahaug, we find that they 
are likewise placed in respect to the weight of their shells, the lightest 
shell corresponding to the fastest growth. From this we can formulate 
the general rule that the growth of any shellfish is directly propor- 
tional to the weight of the shell, which not only seems to hold true for 
the different species, but is applicable to varieties of the same species; 
i.e., a thick-shelled clam grows more slowly than a thin " paper " shell 
variety. 

Variations in Growth. — Many variations are found in the growth of 
scallops. In no two localities is the size identically the same, as can 
be seen by comparing Buzzard's Bay, Cape Cod and Island scallops. 
This variation may be called sectional, and can be attributed to the 
difference in environment, which also applies to local conditions. There 
is also variation in the sets, the average of one year differing from the 
succeeding or preceding years. The size of a scallop is due to two main 
factors: (1) its time of birth, either at the beginning or end of 
the two months' spawning season; (2) the conditions under which it 
lives, whether favorable or unfavorable for rapid growth. Primarily 
the environment and secondarily the time of the set determine in a 
great measure the life of this moUusk. There is another type, indi- 
vidual variation, which is important to consider in presenting the results 
of the growth experiments, as it proves that correct results can only be 
satisfactorily obtained by records of large numbers of scallops. Risser 
(2) remarks on the remarkable uniformity of the individuals of the 
set in Narragansett Bay. No such uniformity has been found under 
the more diverse conditions in Massachusetts waters, and in individuals 
of the same set, especially in the young scallop, variations as great as 
from 1/2 inch to 21/^ inches have been found at the same time and place. 
Between these extremes all grades can be found converging toward the 
average. Even when scallops of the same size are confined in pens 
their growth varies, a fact that can only be attributed to the individual 
traits of the animal. 

Growing Months Man passes through four arbitrary periods in 

life, childhood, youth, manhood and old age, attaining his actual stature 
during the first two, and only adding more flesh as the years pass. 
The scallop, on the other hand, continues to increase in size during the 
adult period, and in fact up to the time of its death has not lost the 
power of growth, although the shell formation in the old scallops is 
somewhat slower than in the younger specimens. But the scallop only 



OF MASSACHUSETTS. 



77 



grows half the time, as all shell formation is accomplished during 
the summer months and no increase in size is found during the cold 
weather. This gives the scallop a resting time between the period of 
youth and adult, and again during its old age, as the average life of 
the animal is from twenty to twenty-six months. 

In following the life of the scallop born in July, growth ceases dur- 
ing December and is again resumed May 1 of the following year, when 
the temperature of the water has reached 45° to 50 °F. The same scal- 
lop ceases growth in the fall, usually in the latter part of November 
(slightly earlier than the young set of that year), when the water has 
again fallen below 45°. Thus, every scallop has two periods of growth, 
corresponding to the two summers of its existence, and two resting 
periods during the winters. The cause of this cessation of growth is 
explained under the topic " Effect of Temperature." 

By monthly measurements of the scallops confined in pens at Mono- 
moy Point during 1906, the relative value of each month was calculated 
and the variation in growth for different parts of the summer was de- 
termined. In the following table each month is given a numerical 
number, representing the gain per cent, for the month, the entire year 
being considered as 100 per cent. (Figs. 84, 85) : — 



Month. 


Per Cent. 


Month. 


Per Cent. 


January 

February, .... 
March, ..... 

April, 

May, 


19.76 
8.33 
10.35 


August 

September, .... 

October 

November 

December 


20.39 

20.08 

18.94 

2.15 


June, 1 

July,i 


100.00 



1 Decrease in June and July due to spawning. 



Length of Life. — Briefly stated, the normal life of the scallop is 
from twenty to twenty-six months, relatively few scallops passing the 
two-year limit. 

Previous to 1906, when this problem was first satisfactorily solved 
by the commission, the question most often propounded by the practical 
scallop fisherman was, " How long does the scallop live ? " In spite of 
the diversity of opinion, which credited the scallop with living anywhere 
from two to five years, the majority of the scallopers believed that two 
years marked the limit of its life, a view which coincided with the 
results of the investigation. Both Ingersoll (8) and Risser (2) agreed 
with this view, but were unable at the time of writing to furnish definite 
proofs. So it fell to our lot to obtain, through a series of observations 



78 THE SCALLOP FISHERY 

covering several years, the necessary data for the actual substantiation 
of the popular theory, and for the establishment of proper legislation 
for the fishery. 

The method of work consisted primarily of continued observations on 
the sets of 1905, 1906 and 1907, following each from birth to death. 
The greater part of the work was done in connection with the growth 
experiments in the different scalloping areas, but more particularly 
with the scallops confined in the Powder Hole at Monomoy Point, 
where favorable opportunity was afforded for obtaining data on the life 
of the scallop. An inclosed, protected body of water, forming a natural 
aquarium of five acres, from which the scallops could not escape; un- 
molested, owing to its being leased by the State for scientific investiga- 
tion; a natural scallop bed with all normal conditions, yet small enough 
for direct control and observation, — were all factors which rendered 
the Powder Hole of especial advantage for the solution of this problem. 
Three sets of scallops were closely followed from birth to death under 
natural conditions, free from many natural enemies and the interference 
of man, and practically unable to escape. Likewise, scallops were con- 
fined in wire pens for two successive seasons and the actual death-rate 
of the old and young scallops compared under the same conditions. 

The life of the scallop can be arranged in four arbitrary stages : 

(1) embryonic life or babyhood, from the time the egg becomes a living 
organism until the animal attaches to the friendly blade of eel grass; 

(2) adolescence, or the period ending when it first spawns at the age 
of one year; (3) the adult period, from twelve to twenty months, 
during the later part of which it is ready for the market; (4) senility 
or old age, from twenty months until the animal dies. 

This last period, that of senility, is the important factor in consider- 
ing the length of life of the scallop, as it is the time of physical decline. 
Old age is marked in the scallop by (1) slower growth and a slight 
thickening in shell formation for those specimens which live over 
twenty-three months; (2) a degeneration in the large adductor muscle 
or "eye," shown by flabbiness and diminution in relative size; (3) an 
increasing amount of foreign growth on the shell. One or more of these 
signs may be absent in individual specimens, but all are true of the 
general type. Old scallops are more sensitive or susceptible to adverse 
conditions than the scallops a year younger, and perish under condi- 
tions which would be survived by the latter. 

The period of senility has no definite beginning. Possibly the scallop 
is on the decline during its adult life, having reached its maximum 
at the spawning season, and then, having outlived its usefulness, awaits 
death. One of the fundamental principles of nature according to the 
old school, as applied to the lower animals, is that life exists only so 
far as it concerns the reproduction of the species, and that animals, 
such as the mayfiy, live only until they reproduce, and then perish. 



OF MASSACHUSETTS. 79 

But with the scallop we have the interesting case of an animal which 
spawns but once and yet lives for nearly a second year, perishing just 
on the verge of another spawning season, — an exact contradiction to 
this principle. This apparent phenomenon might be explained in two 
ways: (1) that a few second-year scallops are useful, as they spawn 
twice; (2) that probably the shallow- water scallop (P. ir radians) once 
had a longer life and more than one spawning season, as its cousin the 
giant scallop {Pecten tenuicostatus Mighels), and that the present Pec- 
ten irradians is a decadent species. 

About the first of March the adult scallops begin to die, and this 
period, when the average scallop is twenty months old, is taken as the 
arbitrary beginning of the period of senescence. In the natural scallop 
beds the majority of the scallops are caught by this time, while the re- 
mainder sooner or later die a natural death, a large proportion perish- 
ing before May or before the twenty-second month. This fact is well 
known to scallopers who fish late in the season, and there have been 
striking instances of large beds suddenly perishing, as at Dennis in 
March and April, 1905. After May the length of life is variable, some 
scallops passing the two-year limit (July) and occasionally living until 
the following October and November (twenty-seven and twenty-eight 
months), but the majority of these die before the twenty-fourth month 
(July). Exact data upon this subject were obtained from scallops 
which had been under observation in wire pens at Monomoy Point for 
two years. Records of death-rate from old age show that, of 465 scal- 
lops alive May 1 (twenty -two months), 32 per cent, remained by July 10 
(twenty-four months) and only 6 per cent. August 2. In July these 
scallops would have been two years old. Scallops one year old, con- 
fined under similar conditions, showed only a slight mortality. 

It is, therefore, fair to assert that under natural conditions, when 
unmolested by the scallopers, but 20 per cent, reach the two-year mark, 
whereas on the scalloping gTounds, unprotected both from nature and 
man, the percentage of old scallops which reach two years is much less 
than in the inclosed Powder Hole at Monomoy Point, and in all proba- 
bility the total which pass the two-year limit is under 10 per cent. All 
rules have their exceptions, and frequently instances occur where scal- 
lops of twenty-eight months (recognizable from two growth lines and 
general appearance) are found. In every scalloping ground an occa- 
sional scallop of this age or older is dredged. More particularly, in 
certain localities small beds of scallops which have passed the age limit, 
are occasionally found, but usually the number in the bed is small. 
Several small beds and one large (Common Flats, Chatham, 1908) have 
come under the observation of the writer, who by no means claims 
that the two-year limit is a hard and fast rule, but rather that there 
are often exceptions, which, however, form but a small per cent, of the 
whole. 



80 THE SCALLOP FISHERY 

The age limit of the scallop ranges from twenty to thirty months. 
We find that the variation is due to several causes: (1) the spawning 
season, which makes possible a difference of two months in the age; 
(2) the environment, favorable or unfavorable, which lengthens or 
shortens the period of Life; (3) seasonal differences, as during a mild 
winter the old scallops are mider less strain than during a severe 
season; (4) the rate of growth and consequently the size of the scallop, 
as the small, slow-growing scallops apparently live longer than the 
large. This was noticeable with the set of 1907 at Monomoy Point, 
which grew very slowly, as compared with the sets of previous years, 
owing to the partial closure of the opening to the ocean and the con- 
sequent lessening of circulation in the Powder Hole during 1908. 
These scallops in the summer of 1909, when two years old, were scarcely 
larger than yearlings, and lived until the following September before 
they began to die, at least six months longer than the normal. In pre- 
vious years in the Powder Hole a small per cent, of the scallops had 
lived until May and a still smaller number until August (twenty-five 
months), but this was the only set, as a whole, to pass to the twenty- 
sixth month, a fact probably explained by their small size and freedom 
from foreign growth. 

The above statements are based on the following facts : — 

(1) The writer has been able to find very few old scallops (twenty- 
seven months) during the fall dredging in waters of the Conamonwealth. 
The scallop fishermen report in each locality the same result, with the 
exceptions above mentioned. This narrows the limit from general prac- 
tical observation to twenty-seven months. 

(2) The reports of fishermen upon the death of scallops in the 
last of the winter and in the spring, as well as the great destruction of 
beds at Dennis, Chatham, etc., prove that the scallop begins to die 
about the twentieth month of its life. This brings the period of death 
and decline between the twentieth and twenty-seventh month, or from 
March until October. 

(3) The sets of 1905, 1906 and 1907 were followed from birth to 
death at the different scalloping sections by observations at stated in- 
tervals, and the results, except for the inroads of the scallopers, were 
conclusively proved by dredging on the scallop grounds. 

(4) Detailed study of the sets of 1905, 1906 and 1907 in the Powder 
Hole, where the scallops were confined for life, shows conclusively that 
the average length of life is two years, even when undisturbed by 
dredging. 

(5) Records from 500 scallops in pens at Monomoy for growth gave 
actual figures for death from old age. 

The connection between the limited life of the scallop and the spawn- 
ing season has been considered under the subject of " Spawning," in 
chapter III., and it is only necessary to again call the reader's attention 



OF MASSACHUSETTS. 81 

to the importance of the short life of the scallop in regulating the 
fishery by law. This knowledge is particularly applicable to protective 
legislation. The length of life permits but one spawning season, when 
the scallop is one year old. After spawning the average scallop is 
valueless for the maintenance of the race, and does not need protection. 
Thus the scallop under one year old, the " seed " scallop, is the only 
one that should be protected by law. No legislation is necessary for 
the scallop past its prime. For this reason restrictive legislation, such 
as limiting the catch by the town law, except when it is to the pecuniary 
advantage of the scalloper, to avoid " glutting " the market, is unneces- 
sary, and only works to the detriment of the fisherman, as all scallops 
not taken will perish before another season. The fisherman should be 
given freedom in his dredging, provided he observes the all-important 
" seed " scallop law, as he can catch all the old scallops without in- 
juring in the slightest degree the future industry. 

The Growth Line. — The shell of the scallop is increased by calcified 
secretions of the mantle, which add fine concentric rings to the growing 
edge. If one observes the shell closely one will find that it is made up 
of microscopic growth lines, due to the method of growth. 

On scallops which reach a second summer there is found a growth 
line, more or less pronounced, which can be likened to the year marks 
seen in cross-section of tree-trunks, and is given the name of the annual 
growth line. Growth lines with the oyster are helpful in determining 
the age, and this line marks the distinction between the adult and 
" seed " scallop, and has attained considerable prominence as the basis 
of the " seed " scallop law. 

The annual growth line is formed in Massachusetts waters about 
May 1, when the scallops resume their gTowth after the cold winter 
months, during which all growth has ceased. Necessarily, during the 
long period of nongrowth, from November to May, the edge of the 
shell has become thickened or blunted by more or less wear, and when 
the new growth is secreted by the edge of the mantle on the inner 
side of the shell a distinct ridge is formed, marking the separation of 
the old and new growth. The location of the growth line varies between 
the limits of 10 to 65 millimeters from the hinge, depending upon the 
size of the scallop when it ceases growing in the fall. We have already 
shown that there is a similar variation in the size of the " seed " scallop, 
owing to difference in its situation and the time of spawning. As a rule, 
the line is 30 to 40 millimeters from the hinge. In some scallops it is 
very prominent, while in others it is difficult to discern at first glance j 
sometimes the shell shows a difference in color between the two parts, 
at other times both the old and new growth are alike, and it is neces- 
sary to run the finger down the shell to determine the ridge. However, 
these cases are the exceptions, and the average growth line is especially 
prominent on the lower or right side of the animal, the upper valve 



82 THE SCALLOP FISHERY 

usually being covered with numerous growths, both plant and animal, 
which may obscure the line. 

As the formation of the annual line is due to cessation of growth 
during the winter, it logically follows that any check for a less or 
greater time will cause slight lines, which are entirely distinct from the 
annual growth line and are by no means as prominent, being merely 
heavier concentric layers. Growth lines of this sort can be produced 
on young scallops at any time by interfering temporarily with their 
growth. The same scalloi^s repeatedly transferred from the spat boxes 
on the raft at Monomoy Point, and. kept in an aquarium for even as 
short a period as one day, could be made to produce as many as three 
or four distinct growth lines. Large " seed " scallops and even adults, 
when transplanted from HarAvieh and Chatham to Monomoy Point, 
always showed the change by the formation of a line of growth. 

The growth line is not caused by the spawning season, as has been 
supposed, since our investigations upon the effect of the spawning on 
gTowth indicate that there is no cessation during this period (June 
and July), and that before the beginning of the spawning there has 
formed during the month of May about Yq of an inch of new shell. 
All our observations for the years from 1906 to 1909 have shown that 
the new growth begins about Maj?^ 1, except for the variation of differ- 
ent years, and that the gTowth line is formed at a time previous to the 
spawning season. 

Although the growth line apj)ears when the scallop is but ten months 
old, it can for all practical purposes be considered as marking the first 
year of the scallop's life. While the spawning season is not completed 
until about the first part of August, these dates are included in the 
closed season, which lasts from April to October, and in a general sense 
the growth line can be associated with the spawning season, and in the 
open fishing season any sealloi? with the annual growth line is ready 
for capture. Risser (2) was the first to advocate the use of the growth 
line to distingnish the difference between the adult and " seed," while 
the Commonwealth of Massachusetts was the first to put into force a 
law based on the growth line as distinguishing the adult from the " seed " 
or immature scallop, which has not spawned. "While we cannot say 
that every scallop with a growth line has spawned, we can definitely 
state that every scallop without a growth line has not spawned and is a 
" seed " scallop. The growth line has thus proved of great practical 
importance in scallop legislation, which is based on the facts obtained 
upon the length of life and spawning of the scallop in Massachusetts 
Avaters. 

Growth during Spawning Season, — The spawning season has the 
wide limits from June 15 to August 15. The greater part of the spawn- 
ing is accomplished during June and the first part of July. Corre- 
sponding to the spawning period there occurs a slowing in the rate of 



OF MASSACHUSETTS. 83 

growth (Fig. 85). Risser (2) has observed a similar occurrence with 
the growth of Ehode Island scallops, but declared that there is a com- 
plete cheek at this period, and to it attributes the origin of the annual 
growth line. This report has demonstrated that the growth line is 
formed at an early period, about May 1, by the resuming of shell 
formation after the nongrowth of the winter months, and has nothing 
to do with the spawning season. Likewise, no decided cheek in the 
growth of Massachusetts scallops is found during the spawning season, 
but rather the scallop continues to grow at about half its normal rate. 
The monthly rate of growth was determined for 1,900 scallops in four 
wire netting pens at Monomoy Point during 1906. It was found, by 
considering the entire summer's growth (May 1 to December 1) as 
100 per cent., that the growth during May was 19.76 per cent., during 
June 8.33 per cent., during July 10.35 per cent., during August 20.39 
per cent., showing that the rate of growth for the month preceding and 
succeeding the spawning season was over twice as fast as for the 
spawning months. 

The reason for this slow gTowth can be attributed to the coincidence 
with the spawning season, and is best exj)lained by assuming that the 
activities of the animal were directed for that period upon the propaga- 
tion of its species, and less energy was used for the secretion of shell. 
Temperature, the great factor in determining growth, does not have any 
influence here, as the water during June and July was warmer than 
during May and colder than August. In fact, all natural conditions 
. affecting the rate of growth were eliminated, leaving the spawning 
season as the direct cause in the lessening of the rate of growth. 

Growth of the Young Scallop. — The young scallop at the age of 
forty-eight hours has increased in size by the formation of the embry- 
onic shell. Previous to this time the ciliated larva was scarcely larger 
than the original egg. The period of first shell formation marks the 
beginning of real growth, which continues for the entire life of the 
scallop during the summer months. Since the gTowth during early life 
has been described in chapter III., it is only necessary to consider the 
growth after the scallop has become readily visible to the naked eye, 
i.e., about %5 of an inch in size. 

The time of appearance of the set depends upon two factors, (1) 
locality; (2) year. During 1906 the visible appearance of "set" was 
recorded as follows: (1) Powder Hole, Chatham, August 7; (2) Stage 
Harbor, Chatham, July 24; (3) Edgartown, August 3; North Fal- 
mouth (Buzzard's Bay), July 20; Marion, July 20; showing a difference 
of fourteen days between two bodies of water not 10 miles apart, and 
an extreme variation of eighteen days. At Monomoy, between 1905 
and 1909, the sets have appeared as early as July 24 and as late as 
August 7, showing the influence of seasonal change. (These dates do 
not indicate the first appearance, but when the average set was readily 



84 



THE SCALLOP FISHERY 



discernible to the naked eye.) Stragglers can be found weeks before 
and after, due to the length of the spawning season. 

The rate of growth of the young scallop is affected by the same 
natural conditions as the adult. Between the sizes of 1 and 15 milli- 
meters, the average gain per day is 0.5 of a millimeter (about %o of an 
inch). As the scallop increases in size the actual growth becomes less. 

The habit of attachment is of gi-eat importance to the scallop, not 
only occasionally saving it from destruction on foul bottom, but raising 
it in a position where the little animal can obtain a better food supply, 
thereby favoring its growth. Eel grass from its abundance proves the 
most common place of attachment, but is often detrimental to growth 
by shutting off the circulation of water. In comparing the growth of 
small scallops in eel grass and outside, the eel-grass scalloj^s show a 
slower growth. 

In summarizing the growth of the young scallop the following points 
are imiDortant: (1) the actual growth begins only with the first shell 
formation; (2) the time of set varies in regard to (a) locality, and 
(b) year; (3) the growth up to 15 millimeters averages %o of an inch 
per day; (4) growth becomes less and less as scallop increases in size 
beyond the 15 millimeter mark; (5) power of attachment aids growth; 
(6) conditions governing growth are the same as for adult; (7) 
growth of the young is faster than for yearling scallops, both in (a) 
actual gain, and (&) in volume. 

Growth of the Average Massachusetts Scallop. — Owing to the varia- 
tion in the growth of the scallop in the different localities, it is difficult 
to strike more than an approximate average for the size of the yearly 
sets and the typical Massachusetts scallop. Two classes of scallops are 
found, (1) the shallow-water or eel-grass scallop, and (2) the deep-water 
or channel variety. The following tables are compiled from the average 
growth in the different localities for a period of three years. The height 
of the scallops is given in millimeters, 25.4 millimeters being equivalent 
to 1 inch. 

The Average Scallop. 





Average Size 


(Millimeters) . 




Set. 


Mayl 
(Ten Months) . 


December 1 
(Seventeen Months). 


Per Cent. 
Gain in Volume. 


1904 

1905 

1906 ■ . 


33.40 
37.50 
31.82 


60.99 
62.30 
60.51 


632.75 
525.78 
678.04 


Average, .... 


34.24 


61.27 


612.19 



OF MASSACHUSETTS. 



85 



Size of Scallop {Millimeters). 



Average. 



Aug. 1, 
Sept. 1, 
Oct. 1, 
Nov. 1, 
Dec. 1, 
May 1, 
June 1, 
July 1, 
Aug. 1, 
Sept. 1, 
Oct. 1, 
Nov. 1, 
Dec. 1, 



2.00 
12.40 
22.64 
32.30 
38.40 
33.40 
38.85 
41.15 
44.01 
49.64 
55.18 
60.40 
60.99 



2.00 
13.76 
25.34 
36.26 
37.50 
37.50 
42.20 
44.27 
46. S4 
51.90 
56.88 
61.76 
62.30 



2.00 
n.82 
21.61 

30.78 
31.82 
31.82 
37.49 

39.88 
42.85 
48.70 
54.46 
59.89 
60.51 



2.00 
12.66 
23.20 
33.11 
34.24 
34.24 
39.. 51 
41.77 
44.57 
.50.08 
55.51 
60.68 
61.27 



Growth in Various Localities. — The growth of the scallop is largely 
determined by its environment. Owing to the diversity of natural 
conditions within small bodies of water more definite conclusions can 
be drawn from special localities than by comparing one locality or 
section with another, owing to the difftculty of determining the average 
growth for so large an area. Nevertheless, it is of interest to compare 
the growths in the different parts of the State in a general way, without 
making too fine a distinction between the individual towns. The follow- 
ing figures are based on a large number of measurements of several 
sets : — 

Size of Scallops (Millimeters). 







The Islands. 


The Cape. 


Buzzard's Bat. 


Date. 


Nantucket. 


Edgartown. 


Chatham. 


Monomoy. 


North 
Falmouth. 


Marion. 


Aug. 1, 
Sept. 1, 
Oct. 1, 
Nov. 1, 
Dec. 1, 
May 1, 
June 1, 
July 1, 
Aug. 1, 
Sept. 1, 
Oct. 1, 
Nov. 1, 
Dec. 1, 








2.00 
10.85 
19.57 
27.79 
28.72 
28.72 
34.53 
36.98 
40.02 
46.02 
51.93 
57.50 
58.13 


2.00 
10.10 
18.09 
25.62 
26.48 
26.48 
32.34 
34.81 
37.88 
43.93 
49.88 
55.49 
56.13 


2.00 
12.43 
22.71 
32.40 
33.50 
33.50 
38.72 
40.92 
43.65 
49.03 
54.33 
59.. S3 
59.90 


2.00 
12.61 
23.05 
32.90 
34.02 
34.02 
39.33 
41.57 
44.35 
49.83 
54.23 
60.32 
60.90 


2.00 
13.77 
25.36 
36.30 
37.54 
37.54 
42.59 
44.72 
47.37 
52.59 
57.77 
62.58 
63.13 


2.00 
16.29 
30.36 
43.64 
45.15 
45.15 
49.94 
51.96 
54.47 
59.42 
64.29 
68.88 
69.40 



Comparison of the Different Sets. — In the second table given under 
the average Massachusetts scallop a comparison of the different sets 
can be found for the whole scalloping district. A better idea of the 
variation can be given in comparing the sets for four years in the same 
locality, the Powder Hole : — 



86 



THE SCALLOP FISHERY 



Set. 



1904, 
1905, 
1906, 
1907, 



Number. 



200 
300 
300 
600 



Size (Millimeters). 



May 1. 



34.. 55 
34.00 
28.09 
21.50 



December 1. 



61.59 
62.90 
59.35 
42.50 



The 1907 set Avas peculiar in showing a much slower growth than the 
previous sets. This was due to the partial closure of the entrance to 
the Powder Hole during the summers of 1907 and 1908, which deprived 
the scallops of the circulation of water which they formerly had. This 
peculiar set has already been discussed in connection with the length of 
life of the scallop, as nearly all reached the age of twenty-seven months. 

Comparison with Rhode Island. — A comparison of the rate of growth 
of the different sections in Massachusetts with the Narragansett Bay 
scallops shows that the average Massachusetts scallop is much smaller 
and less rapid in growth than its neighbor, except in the Buzzard's Bay 
section, where the conditions more nearly approximate Narragansett- 
Bay. This difference is probably due to the warmer water, which per- 
mits earlier spawning and more rapid growth. The Rhode Island 
figures in the following table are taken from the report of Jonathan 
Risser (2) in the Rhode Island Commission of Inland Fisheries, 1904: — 



Size of Scallops (Millimeters) . 



Date. 


Rhode Island. 


Buzzard's 
Bay. 


Cape Cod. 


Islands. 


Average Massa- 
chusetts. 


Oct. 2, 




42.00 


27.86 


22.88 


18.93 


23.20 


Dec. 4, 




44.50 


41.35 


33.76 


27.60 


34.24 


Jan. 11, 




,55.00 


41.35 


33.76 


27.60 


34.24 


March 20, 




56.80 


41.35 


33.76 


27.60 


34.24 


April 21, 




58.80 


41.35 


33.76 


27.60 


34.24 


May 30, 




60.00 


46.27 


39.03 


33.44 


39.51 


July 1, 




60.00 


48.34 


41.25 


35.90 


41.77 


Aug. 1, 




62.75 


50.92 


44.00 


38.95 


44.57 


Sept. 18, 




71.60 


59.02 


52.31 


48.94 


53.42 


Oct. 16, 




79.00 


63.. 38 


57.06 


53.89 


58.11 


Nov. 16, 




81.00 


66.00 


60.10 


56.83 


60.98 


Dec. 3, 




86.00 


66.27 


60.40 


57.13 


61.27 


Jan. 11, 




85.00 


66.27 


60.40 


57.13 


61.27 



OF MASSACHUSETTS. 87 

Age and Growth. — Witti the exception of the winter months (De- 
cember to May), during which no growth takes place, the scallop con- 
tinues to increase in size until its death. The proportionate growth as 
determined by the volumetric increase steadily diminishes after the 
period of first shell formation (the veliger or embryonic shell). On the 
other hand, the actual gain in inches or millimeters is approximately 
constant for the first summei', then slowly decreases during the second 
and even third, provided the animal lives beyond the two-year limit. 
The point is well illustrated by the following experiment: scallops of 
the 1904, 1905 and 1906 sets were suspended in wire cages under simi- 
lar conditions from a raft at Monomoy Point for a period of fifty- 
three days during the summer of 1906 (Fig. 86). The smaller 
(younger) scallops showed a greater capacity for growth both in actual 
increase and in volume. The 1904 set gave an actual increase of 2.10 
millimeters in height, or 112 per cent, in volume, a return of less than 
1% bushels for every bushel planted; the 1905 set 3.94 millimeters 
in height, or 125 per cent, in volume, a return of 1^/4 bushels ; the 1906 
set 10.86 millimeters in height, or 309 per cent, in volume, a return of 
over 3 bushels. From these figures it is evident that the " seed " (1906 
set) gave about twelve times the growth in volume of the yearlings 
(1905 set), and twenty-five times the growth of the 1904 scallops, which 
had lived beyond their allotted life; and that there is a successive de- 
crease, both numerically and volumetrically, in the rate of growth with 
the aging of the scallop. 

Environment and Growth. — Two great factors influence all animal 
and plant life, — heredity and environment. In the ease of the scallop, 
environment seems to possess the greater influence on the variation 
of the species, as varieties are more dependent upon the natural sur- 
roundings than ujDon hereditary characteristics. By environment is 
meant the natural conditions within which the animal lives, and which 
determine its struggle for existence. The question of food, enemies, 
exposure, protection, situation in large or small bodies of water, in or 
out of tidal currents, temperature, etc., are all factors influencing to 
a more or less extent the Hfe and habits of the scallop, making it large 
or small, heavy or light shelled, firm or poor meated, etc. Particularly 
with marine animals does environment largely determine size, shape, 
habits and rate of growth. 

With many aquatic animals larger specimens of the same species are 
found in the great bodies of water than in the small, showing that the 
area of water, either by a more plentiful food supply or in other ways, 
determines the general size. Looking at the matter from a different 
standpoint, that of current, it seems that scallops which have the greater 
amount of water passing over them (which can be compared to resi- 
dence in a larger area) are larger and of faster growth than the scallops 
which do not have the same volume of water. 



88 THE SCALLOP FISHERY 

(a) Growth in Respect to Current. — The most important factor in 
shellfish growth is a good current of water. The use of the word cur- 
rent does not mean necessarily a rapid stream or an exceedingly swift 
flow, but a good circulation of water over the bed. 

The chief office of the current is as a food carrier. The scallop ob- 
tains its nourishment from microscopic plants, called diatoms, which are 
found throughout the water. The amount of this food is approximately 
uniform, and the scallops situated in a current naturally receive more 
food than those in still water. With mollusks the growth is directly 
proportionate to the amount of food, and the scallop receiving the most 
food increases in size most rapidly. A homely comparison can be made 
by likening the scallop in the current to the man seated at a moving 
lunch counter, who is able to continually obtain a new supply of food, 
while his neighbor at the stationary table (the scallop in the still water) 
is limited to the food within reach. For all practical purposes current 
means food, and within limits the increase in curi'ent indicates the 
increase in the amount of food, thus furnishing an index for the rate 
of growth. Theoretically, other factors enter into the problem, such 
as (1) variations in the amount of food in different localities; (2) the 
feeding capacity of the scallop, since beyond a certain maximum value 
an increase in current means no increase in the amount of assimilated 
food; (3) the freedom of the water from contamination and silt, which 
impedes the feeding powers of the animal. The shellfish culturist can 
take the current as his guide for planting, and follow the rule that, 
as long as the flow of water does not harm the planted shellfish in other 
ways, the swifter current gives the faster growth. 

Current not only brings food to the scallop but also furnishes the 
lime in solution which is utilized in building the shell, a process as 
essential in the growth of the scallop as the nourishment of the soft 
parts by the food in the water. The amount of lime in solution varies 
in different waters, but this difference is largely obviated by the changes 
in the current. As an example, a scallop will grow no faster in water 
rich in lime which is comparatively stagnant than it will in water rela- 
tively much poorer where there is a stronger current. 

The third of&ce of the- current is a purely sanitary one. It sweeps 
away the decajdng vegetable matter so destructive to scallops situated 
in thick eel grass, and all other poisonous debris which would otherwise 
kill the scallops by contamination, or at all events would cheek their 
growth. 

The relationship of current to growth has been experimentally shown 
in several ways, all of which demonstrate that in the case of the scallop 
current is the main essential for rapid development. The following 
observations and experiments are cited as confirmatory evidence : — 

(1) Eel-grass v. Channel Scallops. — In observing the catch from 
the scallop beds, it was recorded that the larger scallops always came 



OF MASSACHUSETTS. 89 

from the deep water or channel, while the smaller were taken in the 
eel grass or shallow water. This difference held true to such an extent 
that the scallop fishermen could tell by the appearance of the scallop 
from what section of the bed it came. The shallow-water scallops are 
much smaller, usually proportionately thicker, and have not the large 
" eye " and fine appearance of the channel scallops, which are preferred 
by the scallopers. From a study of the natural conditions of the scallop 
beds, it appeared that this difference in growth was not due to the mere 
change in the depth of water but was due to current. The channel 
scallops on clear bottom receive better circulation of water than in the 
eel grass, which cuts off nearly all flow of water. Places were found 
where scallops in deep water without current showed no more growth 
than the shallow-water variety, while, on the other hand, shallow-water 
scallops situated near the mouth of an estuary where the tide flowed 
swiftly back and forth were nearly as large as the deep-water variety. 
Therefore, while the general distinction between large and small scallops 
appears to be merely that of deep and shallow water, the fundamental 
reason is the presence or the lack of current. 

(2) Penned Scallojis at Monomoy Point. — Two pens were located 
ill the Powder Hole at Monomoy Point in 1906. The first was located in 
an unfavorable situation in shallow water, in thick eel grass which shut 
off all circulation. The second pen was located in a more favorable 
situation, where the eel grass was thin and a gentle circulation was 
caused twice a day by the inflowing of the tide. This pen was situated 
close to the shore and was by no means adapted for more than ordinary 
growth. In comparing the gTowth of the two pens from May 1 to 
August 1 for the same sized scallops it was found that pen 1 gave a 
gain in volume of 12 per cent., while pen 2 furnished an increase of 35 
per cent, for the same sized scallops, or nearly three times as fast as 
pen 1. This furnishes a concrete example of the effect of the lack of 
circulation, as other conditions were very similar in the two pens, 
which were situated only a short distance apart, in the same depth of 
water, and about the same distance from shore. 

(3) Basket Growth on Baft and on Shore. — Scallops of the 1906 
set were obtained from Stage Harbor, Chatham, Sept. 7, 1906, and 
suspended in wire baskets from the raft (Fig. 79), and in pen 2 near 
the shore. The scallops on the raft, which was located in the deepest 
part of the Powder Hole, received the best circulation of water and 
showed a surprisingly fast growth. The difference is brought out by 
comparing the raft growth with the natural growth of the Stage Harbor 
set for the same time, and for the basket growth in pen 2 of the same 
set of scallops. The gain from September 7 to November 22, a period of 
seventy-six days, was 17.28 millimeters for the raft, 14.08 millimeters 
for the Stage Harbor scallops, and 10.40 millimeters for the shore. 
Considering the raft growth as 100 per cent., Stage Harbor would be 



90 THE SCALLOP FISHERY 

81.48 per cent., and the sliore 60.18 per cent. The actual gain in volume 
for each locality would be raft 662 per cent., Stage Harbor 475 per 
cent., shore 293 per cent. (Mg. 88). 

(4) In comparing the growth of penned scallops during 1906 at 
Chatham, Powder Hole, Monument Beach and Marion in reference to 
the natural conditions, the pens with the best circulation of water 
invariably showed the fastest growth, as can be observed in detail by 
referring to the table under artificial growth. 

(5) The Stage Harbor Set. — An excellent opportunity for observ- 
ing the effect of current on the gTowth of young scallops was found at 
Stage Harbor in 1906. The set was located at the entrance to Stage 
Harbor on a flat extending about 90 yards from the east shore to the 
channel, which curves close to Harding's Beach, on the opposite side. 
Thick eel grass covered this flat except near the channel, where it grew 
scatteringly. The water at mean low tide is from 6 to 9 inches deep 
over most of the flat, gTadually deepening at the edge of the eel grass 
toward the channel. The rise and fall of the tide is about 2^ feet. 
At low course tides the greater part of the flat is exposed. The differ- 
ence in the flat i§ mostly due to the tide, which sweeps in and out of the 
harbor at every rise and fall, so that there is a strong current always 
running in the channel. The result is to give that portion of the flat 
near the channel more current than the portion further away, and the 
part near shore hardly any. The young scallops were evenly distributed 
over the flat, although the channel portion was not so heavily set. The 
growth of scallops of the 1906 set was followed by dividing the flat 
into three sections, passing from the shore to the channel, each roughly 
30 yards wide, and by jneasuring the average size of scallops in each 
of these sections at different dates. Four measurements were made, 
Oct. 26, 1906, April 4, 1907, May 1, 1907, and July 1, 1907. By calcu- 
lating the difference in the rate of growth and size at each date, the 
following figures were obtained. Giving the area near the channel 
(the area of fastest growth) 100 per cent., the middle portion would 
have a value of 87.04 per cent., while the shore section would have 
77.79 per cent. These figiires conclusively shoAV the effect of location 
on the growth of scallops, as in this case scallops of the same set mani- 
fested a much greater growth when situated near circulating water. 
Placing the same in measurements as taken July 1, 1907, when the 
scallops were exactly one year old, we would have in current jDortion 
scallops 42.81 millimeters in size, middle, 37.77 millimeters, shore, 32.95 
millimeters, showing a difference of nearly 10 millimeters between the 
current scallops and the shore, possibly 70 yards apart and of the same 
set. Computing the growth of the standard scallop (25 millimeters) for 
each of these areas for a definite period, the following comparative 
gains in volume, 482 per cent., 280 per cent., and 146 per cent, were 
obtained (Pig. 87). 



OF MASSACHUSETTS. 91 

(&) Growth and Soil. — It is impossible to state definitely the exact 
effect of soil upon the growth of the scallop. The character of the 
bottom apparently affects the growth but little, as the scallop rests only 
on the surface and is constantly shifting its position. In this way the 
scallop is different from the quahaug and clam, which lie buried under 
the surface. While the adult scallop is little affected by the nature 
of the soil, the young scallop would soon perish in soft mud were it not 
attached to eel grass during the early period of its life. The best bottom 
seems to be a tenacious sand (sand with a slight mixture of mud) with 
thin eel grass. The most common type, that of the shallow flats, is of a 
sandy nature with various thicknesses of eel grass. In the case of the 
large channel scallop, the soil is either sand, gi'avel, hard mud, shells, 
with but little eel grass. 

The only means of influencing the growth is by the action of the 
organic acids in certain soils which affect the chemical composition of 
the lower valve, the only part of the scallop in contact with the soil. 
Sometimes in cold weather the scallop sinks down in little hollows in 
the soil, bringing more surface in contact with the bottom. Fortu- 
nately, localities of injurious nature are of infrequent occurrence on the 
scallop grounds and are limited in extent. 

(c) Growth in Eel Grass. — The soil indirectly affects the growth of 
the scallojD by the production of eel gi'ass, which is found in more or 
less abundance on the scallop beds. Eel grass, especially on the shallow 
flats, occurs either as (1) thick clusters with open spaces intervening, 
(2) thinly scattered or (3) thick masses. Only in the last case is eel 
grass a serious check to growth, as it then cuts off a proper circulation 
of water, which is the main essential for rapid development, although 
in the other two types there is more or less interference, according to the 
thickness of the eel grass. By a comparison between gTOwth on clear 
sand bottom and in thick eel grass, where other conditions were approxi- 
mately the same, the scallops on the clear bottom show a greater rapidity 
of growth than those within the grass, showing that the difference was 
mainly due to a lack of circulation. 

(d) Effect of Temperature. — The factor next in importance to cur- 
rent in determining the growth of the scallop is temperature. The 
scallop needs a temperature over 45° F. for growth, thus differentiating 
the growing months (May 1 to December 1) from the winter months 
(Fig. 89). Naturally, cessation of growth would be attributed to a 
lack of food. While by actual count there is a decrease in the amount 
of food (diatoms) in the water about December 1, it is not sufficient to 
account for the cessation of growth at this date. Indications point to 
the fact that the activity of the scallop in procuring food has declined, 
as the animal has become sluggish with a lowering of the water tempera- 
ture, and during the winter months remains inert on the bottoin, nestling 
in little hollows in the sandy soil. 



92 THE SCALLOP FISHERY 

Waters of high temperature usually show more rapid growth, prob- 
ably due to (1) the earlier start in the spring and longer season, (2) 
more rapid gTOwth throughout the summer months from an increased 
food supply. Diatoms multiply more rapidly in warm waters and the 
food supply is consequently greater. The effect of temperature can be 
seen by comparing the sealloi^s of Cape Cod and Buzzard's Bay. The 
former do not attain the size of the latter, which are the largest scallops 
produced in the CommonAvealth. The same comparison holds true 
between Rhode Island and Massachusetts, as in the warmer waters of 
Narragansett Bay the scallops develop more rapidly. While in both 
eases other natural conditions play an important part, it is only fair 
to assume that temperature is a most important factor. 

(e) Grotvth and Salinity. — The oyster is extremely sensitive to 
changes in the salinity of the water, both in regard to spawning and 
gTowth. The gTowth of the scallop, on the other hand, is not materially 
affected by these changes. A sudden decrease in salinity, as after a 
severe rain, often idlls young scallop larvae, and transferring scallops 
from water of one density to another during the breeding season has 
been found to check the spawning. 

Scallops are found in waters ranging in density from 1.010 to 1.027, 
i.e., an equal mixture of salt and fresh, as in mouths of rivers, to 
extreme salinity. Rough experiments have demonstrated that scallops 
live and gTow equally well between these limits, and that any differences 
in growth are due to other conditions. 

(/) Depth of Water. — The question of the most favorable depth for 
growth is of importance to the scallop planter. In nature scallops are 
found at any depth, from flats exposed at low tide to 60 feet, although 
the usual limits are less than 25 feet. In too shallow water severe 
winters destroy the sets, so the scallop should be deep enough to escape 
the ice. As shown by the channel v. eel-grass (shallow water) scallop, 
the greater growth occurs in the deep waters; but, as has been stated, 
this is essentially due to the better circulation in the channel. 

Scallops were suspended in wire baskets from the raft in the Powder 
Hole at different depths during the summer of 1906. The water was 
20 feet deep. Four baskets, each containing 100 " seed " scallops 
about 20 millimeters in size, were suspended for seventy-six days at 
6, 7, 8 and 9I/2 feet from surface. When measured a regular decrease 
of about one millimeter per foot was found, the 6-foot basket evidencing 
the greatest gain, and the rest less in definite order, ending with Qi/^- 
f oot basket. These figures indicate that the best depth for this particular 
locahty was about 5 feet from the surface. Similar experiments with 
older scallops gave negative results. 

Artificial Growth. — The greater part of the growth experiments on 
the scallop were conducted under the artificial conditions that would be 
employed in scallop culture. In order to record the rate of gxowth 



OF MASSACHUSETTS. 93 

correctly, it was necessary to have some means of confining the scallops. 
This was done in three ways: (1) pens of wire netting; (2) wire cages; 
(3) an inclosed body of water, the Powder Hole. Only the first two 
can properly be considered artificial, as in the Powder Hole the scallops 
were in their natural environment. The records were taken at monthly 
intervals, three measurements being taken of each scallop. 

The pens were located at Monomoy Point, Chatham, Nantucket, Mon- 
ument Beach, Marion, and in the Annisquam and the Essex rivers. The 
size of the pens ranged from 40 to 400 square feet, either of sufficient 
height to extend above the average tide, or covered with a netting to 
prevent the scallops escaping. The posts were made of 2 by 3 feet 
joists firmly fixed in the soil and placed at sufficient intervals to hold 
the netting taut. Wire netting (1^-inchmesh) and old seines were used, 
the gTeatest difficulty being to secure the bottom firmly, which was done 
by base-boards and by fastening the netting in the sand with long 
wooden pegs. (A complete description of the construction of the pens 
is given in chapter VII.) It is only fair to state here that pens can 
probably be improved in such a manner that better results can be ob- 
tained, and many of the difficulties of artificial culture can be eliminated. 

(a) Artificial compared with Natural Growth. — For some reason 
the scallops in the pens do not grow as rapidly as the unconfined scallops 
in the same locality. This is proved by a comparison of the growth of 
penned and unpenned scallops in the Powder Hole in 1905, and also by 
the table of comparative growths in the pens in the various localities 
during the summer of 1906. In the first ease the growth approximated 
14.30 millimeters for the penned, as compared with 25.04 millimeters 
for the unpenned, showing a gain of 10.74 millimeters, or 75 per cent. 
The average growth from five pens was 16.77 millimeters, as compared 
with 26.29 for the unpenned, showing a difference of 9.52 miUimeters, 
or 56.8 per cent. It seems peculiar that merely limiting the range of 
the scallop should have this detrimental effect upon its growth. Several 
explanations are in order: (1) lack of food by overcrowding in the 
pens; while this is a very probable explanation, as the scallops were 
much thicker in the pens than without, it does not seem to hold true 
for the pens which contained but few scallops, as these no wise differed 
from the others; (2) the accumulation of seaweed and other plant life 
on the meshes of the netting, which prevented the proper degree of 
circulation; (3) the lessened activity of the scallop as compared with 
the freedom of those without, i.e., lack of exercise. Probably to no one 
of these explanations can be attributed the whole cause, but rather that 
all three are more or less involved. 

This fact, when apphed to scallop culture, is important, as the planter 
would naturally be desirous of at least attaining as good a growth, if 
not better, than under natural conditions, and yet if he confines the 
scallops in small pens he is unable to obtain a maximum yield. There 



94 



THE SCALLOP FISHERY 



is no reason to believe that this difficulty cannot be overcome by the 
construction of improved pens, and by requisite care in cleaning. On 
the othe"r hand, as is stated in chapter VI., under " Artificial Culture," 
scalloj) culture can only be successfully conducted in inclosed bodies of 
water, since the expense of erecting pens would offset the profits. 
Pens should merely be used to hold the immediate catch for market and 
rarely utilized for rearing purposes. 



Penned and Unpenned Scallop Growth in 1906. 





Penned. 


Unpenned. 


Location. 


Gain 
(Millimeters). 


Gain in Volume 
(Per Cent.) . 


Gain 
(Millimeters). 


Gain in Volume 
(Per Cent.). 


Powder Hole, 

Chatham 

Monument Beach, 
Marion 


15.84 
24.25 
16.00 
11.00 


406.00 
726.00 
411.00 
280.00 


28.90 
26.40 
25.59 
24.25 


965.00 
831.00 
790.00 
729.00 


Average, 


16.77 


456.00 


26.29 


828.00 



(6) Results from Artificial Growth. — ^ The greater part of the points 
enumerated in this chapter were obtained from the experiments upon 
confined scallops, which, although merely approximating natural condi- 
tions, were the only means available for arriving at definite conclusions 
upon the growth of the scallop. For comparative work and as supple- 
mented by definite observations on the natural beds, they proved of 
great value in respect to the following: (1) length of life; it was neces- 
sary to confine the scallops to ascertain the duration of life, which 
results were sujDplemented by use of tagged and uneonfined scallops; 
(2) the growing months and the relative economic value of each month, 
mainly determined from the pen experiments at Monomoy; (3) the 
comparative rate of growth of the different sizes, determined from pen 
and cage experiments; (4) growth during the spawning season; (5) 
the effect of environment and natural conditions which affect the rate 
of gTowth, resulting from (a) currents, (&) soil, (c) eel grass, {d) tem- 
perature; (6) density; (7) depth of water. These were determined by 
a comparison of the natural conditions for each pen and the effect 
which each had upon growth. 

Among others, the following facts have been demonstrated by arti- 
ficial growth experiments : — 

(1) Scallops transplanted to Waters North of Boston. — Three pens 
were planted in May, 1906, two of these in the Essex River and one in 
the Annisquam River, with scallops brought from Cape Cod. Unfortu- 
nately, no records could be obtained as the pens were swept away by 
the swift tidal currents of the north shore rivers, and no trace of the 



OF MASSACHUSETTS. 95 

scallops were obtained. Undoubtedly there are but few places in these 
rivers where the temperature and other conditions are such that trans- 
planted scallops can live. As a whole, the region is unsuited for the 
scallop and no industry can ever be expected. 

(2) Deformity of Shell of Scallops grown under Artificial Condi- 
tions. — Scallops confined under artificial conditions frequently show 
deformities. In nature, deformities in shell occur occasionally, usually 
being due to the loss of part of the secreting mantle or by contact with 
some object. The young " seed " scallops confined in the wire cages fur- 
nished three types of deformity: (1) a general type, the ratio of width 
to height being much gxeater than in the normal " seed; " (2) the thick- 
ness of the caged ^' seed " exceeded the thickness of the normal scallop ; 
(3) many individuals in the cages showed indented shells, angular pro- 
jections corresponding to the position in which they had rested in eon- 
tact with the wire sides, and numerous other malformations occasioned 
by their cramped quarters. All these factors operated against perfect 
work in recording the growth of the caged scallop. 

(3) Growth of Small and Large Scallops of the Same Age. — The 
size of the " seed " scallops of any set vary gTeatly, but by the time they 
are ready for market the size is more nearly uniform for scallops under 
similar conditions, i.e., there is less individual variation. One of the 
surprising facts noted was that the penned scallops, by the increased 
rapidity of gTOwth, caught up with the larger before the season was over. 
In one pen two lots of scallops which on May 1 measured 38 and 46 
millimeters respectively, by December 1 were each 60 millimeters in 
height, the smaller scallops having made up the difference of % of an 
inch, and had a gain in volume of 477 per cent., while the 46-millimeter 
scallop had only increased 249 per cent, in volume (Fig. 90). In sev- 
eral eases this fact was observed and substantiated, likewise from 
measurements of the natural scallops, showing that the scallops which 
are backward in growth the first year, either from poor location or 
late spawning, when placed under favorable conditions have a greater 
potential energy for growth than the larger "seed," and practically 
make up the loss in the first season by increased gain during the second. 

(4) Individual Variation and Heredity.- — Each scallop has its indi- 
vidual characteristics. Take any number of scallops of the same size, 
no matter how few, and let them grow for a month or more. When 
measured considerable variation will be found, in spite of the fact that 
all the scallops had the same advantages and were under the same con- 
ditions. It is due to the individual variation in the growing powers of 
the different scallops, such as, e.g., their capacity for feeding or shell 
secretion, and is primarily the result of either injury or heredity. Indi- 
vidual scallops have been marked and it has been found that generally 
a slow-growing scallop will keep the same rate during the entire season, 
in spite of changed position. 



96 



THE SCALLOP FISHERY 



(5) Overcrowding. — Overcrowding tends to decrease the general 
rate of growth, as too many mouths are drawing from a limited food 
supply, and unless there is considerable circulation of water the amount 
per capita is limited. The stronger the current the greater number can 
be planted per square foot. The wire cages suspended from the raft 
demonstrated the effects of overcrowding. Under uniform conditions 
" seed " scallops averaging 21 per cubic foot gained 21.45 millimeters in 
height, or 1,092 per cent, in volume, in seventy-six days, while those 
averaging 153 per cubic foot gained 15.59 millimeters, or 659 per cent, 
in volume, a difference of 433 per cent. In this case the circulation of 
water was excellent, yet the difference was decidedly marked. 

(6) Cage v. Natural Growth for Small Scallops {"Seed ") . — The 1906 
set on the raft was recorded by confining some in wire cages of small 
mesh, increased in size as the scallops became larger, and by measure- 
ments of the scallops which naturallj?^ wei-e attached to the different spat 
boxes. The result was that the caged scallops gained only 15.70 milli- 
meters between August 17 and November 22 (ninety-seven days), both 
classes being 3 millimeters in size on AvigTist 17, while the natural set 
gained 29 millimeters in the same period. The dift'erence is explained 
by (1) lack of food, the meshes of the cage shutting off the circulation 
of food organisms; (2) abnormal growth, due to deformities resulting 
from cage environment. It is impossible to overcome these difficulties 
in obtaining the rate of growth of the scallop from caged specimens. 

1905 Set during 1906. 



May 1, 1906, 
June 1, 1906, 
July 1, 1906, 
Aug. 1, 1906, 
Sept. 1, 1906, 
Oct. 1,1906, 
Nov. 1, 1906, 
Dec. 1, 1906, 
Gain, 



Gain in volume for 
standard 30 milli 
meter scallop, . 



PowDEE Hole. 



Pen 1. 



,00 mm. 
.85 mm. 
,27 mm. 
.80 mm. 
.83 mm. 
85 mm. 
.81 mm. 
.92 mm. 
.92 mm. 



Pens. 



45.30 mm. 
48.43 mm. 
49.75 mm. 
51.39 mm. 
54.62 mm. 
57.80 mm. 
60.80 mm. 
61.14 mm. 
15.84 mm. 



Pens. 



42.48 mm. 
47.27 mm. 
49.29 mm. 
51.80 mm. 
56.74 mm. 
61.61mm. 
66.20 mm. 
66.73 mm. 
24.25 mm. 



Monument 
Beach. 



Pen 4. 



47.50 mm. 

50.18 mm. 
51.60 mm. 
53.40 mm. 
56.80 mm. 

60.19 mm. 
63.15 mm. 
63.50 mm. 
16.00 mm. 

411s« 



Makion. 



Pen 5. 



50.46 mm. 
52.63 mm. 
53.55 mm. 
64.69 mm. 
56.93 mm. 
59.14 mm. 
61.22 mm. 
61.46 mm. 
11.00 mm. 



OF MASSACHUSETTS. 



97 



Natural Conditions. 



Size of pen, 

Location, . 

Distance from 

shore. 
Current, 

Soil, . 

Eel grass, . 

Rise of tide. 

Depth of water. 

Salinity, . 

Number of scal- 
lops. 
Enemies, . 



Pen 1. 



15 X 10 feet, . 
Bay, . 
30 feet. 
None, . 
Coarse sand, 
Thick, . 
^'A feet, 
l}i feet, 
1.021, . 
610, 
Oyster drill. 



Pen 8. 



40 X 10 feet, 
Bay, . 
20 feet, 
Fair, . 
Coarse sand 
Thin, . 
iVz feet, 
2>^ feet, 
1.021, . 
2300, . 
Oyster drill. 



7x6 feet, . 

Entrance to 

harbor. 
270 feet, 

Excellent, 

Hard yellow 

sand. 
Very thin, 

3.3 feet, 

1 foot, . 

1.020, . 

100, 

Starfish, 



Monument 
Beach. 



Pen 4. 



sand 



10 X 10 feet, 

Bay, 

20 feet. 

Fair, 

Gravel, 

None, 

4 feet, 

2J^ feet 

1.019, 

325, 

Oyster drill. 



Pen 5. 



10 X 10 feet. 
Small cove. 
150 feet. 
Slight. 
Soft mud. 
Thick. 
4 feet. 
IK feet. 
1.017. 
33S. 
Oyster drill. 



' " ■ ' CHAPTER YI. — THE INDUSTRY. 

While a description of the natural conditions of the beds, the methods 
of capture and the preparation of the scallop for market may prove of 
slight information to the fishennan, the general public has little knowl- 
edge of the methods used in the fishery. For this reason the following 
pages are primarily intended for the average reader, although different 
methods are employed in the various parts of the coast, and often the 
sealloi? fishermen in one locality are only familiar with the methods used 
in their immediate vicinity. In such cases information as to methods in 
other localities as regards implements, boats, dredges, etc., is an im- 
portant factor in the development of the industry, and since the aim of 
this report is the improvement of the scallop fishery, no apology is 
necessary for the repetition of special parts of the Mollusk Report 
of 1909. 

The Fishing Grounds. 

Scalloping territory is a variable asset, as the beds are constantly 
changing according to the location of the yearly sets, and a description 
of the grounds for any reason may vary from preceding or succeeding 
periods. In a general way the location and distribution of the scallop 
beds are shown on the accompanying map (Fig, 78). For greater detail 
the reader is referred to the Mollusk Report of 1909, 

The scalloping territory, which is entirely confined to southeastern 
Massachusetts, can be separated into four main divisions: (1) the north 
side of Cape Cod; (2) the south side of Cape Cod; (3) Buzzard's Bay; 
(4) the islands of Martha's Yineyard and Nantucket. 



98 THE SCALLOP FISHERY 

North Side of Cape Cod. — While there is some evidence from old 
records that scallops once existed as far north as Boston, they are not 
found at the present time further north than Plymouth, where it is 
reported that within the past few years a few could occasionally be 
gathered on the eel-grass flats of the harbor. Between Plymouth and 
Provineetown scallops can be obtained at Barnstable, Brewster, Well- 
fleet and ProvincetoAvn, but no extensive industry is carried on. This 
section, owing to certain unfavorable conditions, probably never will 
be suitable for a prosjoerous fishery such as is maintained on the south 
side of the Cape. 

Natural conditions are practically the same for the entire section. 
Plymouth, Barnstable, Wellfleet and Provineetown harbors are in many 
respects similar, except that the two latter have different soil. The 
chief characteristic is the great rise and fall of the tide, averaging about 
10 feet, which leaves exposed at low water vast areas of flats on which 
the scallops perish during the winter. Another unfavorable factor is 
the extreme swiftness of the tides, for example, in Barnstable and Ply- 
mouth harbors, which cause a continual shifting of the sand bars and 
wash the scallops upon the flats, where they are at the mercy of the 
elements. Every form of sea life has its range, and Cape Cod may be 
considered as the northern barrier in the distribution of the scallop. 

The primitive methods of gathering the scallops by hand from the 
exposed flats, or by pushers and dip nets in the shallow water, is fol- 
lowed. No regular dredging is carried on, and the industry, except 
during the last two years at Brewster, has not been considered of any 
importance. The origin of the scallops which wash ashore on the flats 
of Cape Cod Bay at Provineetown and Brewster is unknown. The 
fishermen believe that in the deeper waters of the bay is a large bed, 
which furnishes the scallops that are annually washed ashore. In spite 
of the fact that this bed has never been located, there is every reason 
to believe in its existence. 

(a) Barnstable Harbor.- — ^ On the eel-gTass flats on the south side of 
the harbor a feAV scallops can be found at the present time; but there 
is not a sufficient number to make a regular business, such as was carried 
on in 1877-78, according to Clark (11). The chances are that a severe 
winter or some other adverse condition killed all the scallops in this 
locality, and thus, by destroying the spawners, rendered impossible any 
future supply. 

(&) Orleans and Brewster Flats. — Along the bay shore of these 
towns, about % mile from the high-water line, scallops are found every 
winter in more or less abundance, varying from a scant few to a suffi- 
cient quantity, as in 1908-09, to make a profitable business for the 
town of Brewster. The scallops, unless gathered, soon perish, as they 
lie on the flats fully exposed to the chill of winter. 



OF MASSACHUSETTS. 99 

(c) Well-fleet Harbor. — Scattering scallops are found near Billing-s- 
gate Island, on the north side of the harbor, and east of Jeremy's Point, 
but no regular fishing is carried on. 

{d) Provincetown Harbor. — On the shore of the east bend of the 
harbor, toward Truro, scallops are washed ashore in varying amounts 
by the southwest winds. About fifteen years ago scallops were reported 
as numerous, and it was not uncommon for a man to pick up 5 bushels 
at one tide, but since 1900 few scallops have been found. 

South Side of Gape Cod. — This section comprises the towns on the 
south shore of the Cape from Chatham to Mashpee. Here conditions 
are extremely favorable, except for an occasional southerly blow, which 
at times is sufficiently strong to wash the scallops in windrows on the 
shore. Only the shellfish in the exposed waters on the open coast are 
subject to this loss. The other conditions, such as a small rise and fall 
of tide (about 2 feet), good circulation of water, suitable bottom and 
depth of water, are all favorable to the habitation of scallops. On some 
flats during the low-running winter tides there is considerable exposure, 
as on the common flats of Chatham, and many scallops perish annually. 
The greater part of the fisherj' is conducted on the open coast, at some 
distance from shore, by dredging, or with " pushers " on the low flats 
which skirt the shore. Scallops are also plentiful in the inclosed bays 
which line the shore, such as Stage Harbor, Chatham ; Lewis Bay, Hyan- 
nis; and Oysterville Bay, Barnstable. The average size of the scallop 
in this section is 2.13 inches. Few natural enemies are found. Starfish 
and oyster drills are present, but ■ not in sufficient number to be of 
material damage. The total area comprised in this section is 12,700 
acres. 

(a) Chatham. — Scallops are found only in the southern waters of 
the town. Between Inward Point and Harding's Beach many acres of 
eel-grass flats, sheltered from the open ocean by Monomoy Island, fur- 
nish excellent grounds for scallops. The entire area of these grounds 
is approximately 2,000 acres, although this whole territory is never 
completely stocked in any one year. During the season of 1907-08 the 
following places constituted the scalloping grounds : — 

(1) Island flats in Stage Harbor, on the east side of the channel, 
opposite Harding's Beach, furnish a number of scallops, which are 
caught the first of the season, as these flats were near the town. 
Here the water is not more than II/2 to 2 feet deep at low tide, and 
thick eel grass covers the greater part except near the channel. 

(2) Directly south of Harding's Beach lies John Perry's flat, com- 
monly known as '' Jerry's," where there has been good scalloping for 
many years. 

(3) The western half of the Common Flats furnished the best scal- 
loping in 1907-08, as the scallops, though small (6 pecks to a gallon). 



100 THE SCALLOP FISHERY 

were plentiful. These flats run nearly dry on low course tides, and 
are covered with eel grass. Nearly every year there is a heavy set of 
scallop seed, which, because of the exjoosed nature of the flats, is 
wholly or partially destroyed. The entire set was destroyed in the win- 
ter of 1904-05, while 30 per cent, was lost in 1906-07. 

(4) On the flats just south of Inward Point was another bed of 
scallops. 

(5) In the bend north of Inward Point scallojDS Avere plentiful. 

(6) On the northwest edge of the Common Flats scallops can be 
dredged over an area of 160 acres at a depth of 5 fathoms. These 
are of good size, opening 3V2 Cjuarts to the bushel. 

(&) Harwich. — The scallop territory of Harwich covers an extensive 
area on the south side of the town, and in some places extends for a 
distance of from 2 to 3 miles out from shore. Usually the scallojDS are 
found, as in the last season (1907-08), outside the bar, at a distance of 
3 miles from shore, where they can be taken only by dredging from sail 
or power boats. The intervening body of water sometimes contains a 
few scallops in a quantity to make a commercial fishery. The total 
area of the scallop grounds is about 3,200 acres. The bottom is mostly 
sandy, with patches of eel grass. 

■(c) Dennis. — The scallop grounds of Dennis and Yarmouth are 
common property for the inhabitants of both towns, while other towns 
are excluded from the fishery. The West Dennis scallopers fish mostly 
on the Yarmouth flats at the mouth of Parker River, and between Bass 
and Parker rivers on the shore flats. There is also scalloping along the 
shore on the Dennis grounds. These grounds are for the " pushers." 
Dredging is carried on at Dennisport, and the boats cover a wide terri- 
tory at some distance from the shore. The town possesses a large area, 
which either has scattering scallojDS or is well stocked one year and 
barren the next. Nearly 2,250 acres of available territory are included 
in the waters of the town. The flats, which are of sand with thick or 
scattering eel grass, according to the locality, afford a good bottom for 
scallops. Were it not for the eel grass, the scallojos Avould perish by 
being washed on the shore by southerly Avinds. 

(d) Yarmouth. — The scallop grounds of Yarmouth are on the south 
side of the town, on the flats which border the shore from Bass River to 
Lewis Bay. Part of the waters of Lewis Bay belong to the town of 
Yarmouth, and scallops are found over all this territory. The natui'e 
of the bottom is the same as at Dennis and Barnstable. The total area 
of scallop territory is estimated at 2,250 acres. The scallop grounds of 
Dennis are open to Yarmouth scallopers. 

(e) Barnstable. — Although the scallop industrj^ on the north coast 
of the toAvn is extinct, it still flourishes as of old on the south coast. 
The bulk of the business is carried on here, and nearly all the shipments 
are made from Hj'annis and Cotuit. The grounds of Cotuit are quite 



OF MASSACHUSETTS. 101 

small, extending over an irregular strip of 100 acres. The bottom is 
mostly muddy, and covered with patches of eel grass. All the rest of 
the bay, where the bottom is more suited for oyster culture, is taken up 
by grants. This scalloping area, although small, is free to the scallopers 
of Osterville, Cotuit, Marston's Mills and Hj'annis, and even where 
heavily set it is soon fished out. The scallop territory near Hyannis 
comprises 2,700 acres, in the following localities: (1) Lewis Bay; (2) 
near Squaw's Island; (3) Hyannisport harbor; and (4) the shore 
waters. At Hyannisport small scallops are taken with " pushers " in the 
shallow water, while large scallops are taken by dredging in the other 
three localities. Scallops are found in different parts and in varying 
abundance each year. 

(/) Mashpee. — The scallop territory of Mashpee lies in the Poppo- 
nesset River and Bay, comprising at most 200 acres. For the last eight 
years there has been no scallop industry in the town. A few scallops 
are occasionally gathered for home consumption. 

Buzzard's Bay. — The third section comprises the waters at the head 
of Buzzard's Bay, the most protected and perhaps the most favorably 
situated of the scalloping localities in respect to natural conditions. 
The warmth and excellent circulation of the water as it courses in and 
out of the numerous little bays and inlets are favorable to rapid growth, 
and render possible the production of the large scallop, averaging 2.73 
inches, found in this section. The medium rise and fall of the tide 
(about 4 feet) and the eel-grass bottom give the scallops abundant pro- 
tection in contrast to the exposed situation in other localities. In spite 
of these favorable surroundings great numbers of scallops perish from 
the severe winters and from the attacks of their natural enemy, the 
starfish. For seven years previous to the season of 1907-08 the scallop 
fishery had been a failure in these waters, said to have been due to the 
inroads of this pest, but since that date it has again become of im- 
portance. The scalloping territory comprises 11,100 acres and is situ- 
ated in the towns of New Bedford, Fairhaven, Mattapoisett, Marion, 
Wareham, Bourne and Falmouth. The fishing is carried on almost 
wholly by dredging. 

(a) New Bedford, — The scallop area comprises approximately 400 
acres, principally in the Aeushnet River and Clark's Cove. 

(h) Fairhaven. — This town shares with New Bedford the scalloping 
gTounds of the Aeushnet River, and has in addition a much larger terri- 
tory around Sconticut Neck and West Island. The grounds comprise 
about 2,500 acres, most of which is unproductive or productive only at 
intervals. 

(c) Mattapoisett. — The scallop territory, comprising an area of 
1,200 acres, much of which is open and exposed, is in general confined 
to the following localities: Nasketucket Bay, Brant Bay, Brant Island 
Cove, Mattapoisett harbor, Pine Neck Cove and Aucoot Cove. 



102 THE SCALLOP FISHERY 

(d) Marion. — The scallop gToiinds of the town extend over an area 
of 1,500 acres, situated on both sides of Great Neck, and extending 
from the Wareharti line to Aueoot Cove. 

(e) Wareham. — Situated at the head of Buzzard's Bay, this town 
possesses a considerable water area which is suitable for scallops. The 
entire territory, embracing approximately 2,500 acres, extends in a 
southAvesterly direction from Peter's Neck, including Onset Bay, to 
j^biel's buoy, and from there to Weweantit Eiver. Scallops are also 
found in the Wareham River. Scallops are mostly found in the deep 
water, which makes dredging the only profitable method of scalloiDing in 
this locality. 

(/) Bourne. — The available scalloping territory covers aj^proxi- 
mately 3,000 acres, extending frora Buttermilk Bay along the whole 
coast of the town to Cataumet. 

(g) Falmouth. ■ — Scallops are found in Squeteague Pond, Wild 
harbor. North Falmouth and in West Falmouth harbor. Scallops are 
occasionally present in small quantities in Waquoit Bay, on the south 
shore of the town. 

The Islands of Nantucket and Martha's Vineyard. — This section 
bears evidence of the jDroteetion of a fishery by nature and the ability 
of the inhabitants to foster a valuable industry. In both islands the 
natural conditions are such as to supply the maximum aid in the preser- 
vation of the fishery. The scallop territory, for the most part, lies in 
protected bays, Nantucket harbor. Cape Poge Pond and Vineyard 
Haven. Certain parts of the territory are exposed and subject to condi- 
tions unfavorable for the scallop, but the greater portion is well inclosed 
and favorably suited for regulating the distribution of " seed." The 
rise and fall of the tides is slight, not averaging more than 2 feet. A 
variety of bottom mostly covered with eel grass is found in all the 
localities, while the depth of water over the beds averages from 10 to 15 
feet, rarely exceeding 25. 

In this section, no matter how scarce the supply may be elsewhere 
in the State, the yield of scallops is constant. While there is more or 
less variation in the diiSerent years, extreme scarcity and superabun- 
dance, so common in the other sections, occur here but rarely, and the 
scallop supply from this locality is considered the most dependable in 
Massachusetts. The total area comprised in this section is 7,300 acres. 

(a) Nantucket. — The grounds lie both in Nantucket harbor and in 
Maddequet harbor, on the west end of the island. The former of these 
is the larger and more important, as the fishery is near the town. When 
the scallops become scarce in Nantucket harbor, the scallopers adjourn 
to the fresher beds of Maddequet. Nantucket harbor contains approxi- 
mately 3,000 acres of scallop territory; Maddequet and Muskeget, 1,500 
acres. 



OF MASSACHUSETTS. 103 

(b) Edgartown. — The important grounds are in Cape Poge Pond 
and in Edgartown harbor, while occasionally beds of scallops, especially 
" seed," are found in Katama Bay. These grounds comprise an area 
of 2,000 acres, chiefly of grass bottom. 

(c) Vineyard Haven. — The scalloping grounds of Tisbury are in 
the harbor at Vineyard Haven, Only Vineyard Haven fishermen make 
a business of scalloping here. The scallop grounds comprise an area 
of 800 acres. 

The Present Industry in Massachusetts. 
In considering the scallop industry the following points should be 
noted: (1) It has been necessary to record as scallop area any grounds 
where scallops have ever been found, in spite of the fact that only 
a portion of this total area is in any one year productive. (2) The 
boats engaged in the scallop fishery are but transitory capital, which 
is utilized, outside of the scallop season, in other fisheries. (3) The 
quahaug and scallop fisheries in many towns supplement each other, 
as the same men and boats are engaged in both industries. (4) The 
length of the season varies in the different localities. In New Bedford 
and Fairhaven the scallops are mostly caught in a few weeks, as many 
boats enter the business temporarily. This necessarily gives an excess 
of invested capital and a small production. In these two towns the 
number of scallop licenses are recorded, as showing the number of men 
engaged in the fishery, while as a fact but a small part of these are 
steadily engaged in the industry. 



104 



THE SCALLOP FISHERY 



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OF MASSACHUSETTS. 105 



The History and Development of the Scallop Industry. 

In considering the rise of a fishing industry, it is often difficult to 
state exactly the year when the industry started, as there are differences 
of opinion as to how large a fishery should become before it could be 
justly considered an industry. The seallojD fishery has existed for years, 
but did not become an established industry of the Commonwealth before 
the year 1872. At that time there was scarcely any demand for scallops 
and the catch was marketed with difficulty. Since then the market for 
the scallop has steadily increased, until the supply can hardly meet the 
popular demand. 

It seems almost incredible that the scallop as an article of food 
should once have been scorned and practically unknown. In former 
years the majority of people looked upon the highly colored shellfish, 
with its beautiful shell, as poisonous and unfit for the table, in the same 
manner as our country fathers considered the " love apple," now the 
tomato, as only an ornament for the garden. Popular taste and opinion 
have changed, and the formerly despised scallop is now considered as an 
important part of our sea food. What has been true with the scallop 
applies equally well in regard to our future attitude towards sea food; 
many species of fish and shellfish now considered as unwholesome will, 
in the years to come, be considered as articles of food. 

In early colonial days the scallop was frequently mentioned by the 
Avriters of that period, possibly because the attractive appearance of 
the fan-like shell rendered it a conspicuous object on the beaches, and 
possibly because the scallop shell had been from the time of the Crusades 
of emblematic significance. The first use of the scallop was as fertilizer. 
When bloAvn ashore in quantities, the farmers occasionally came with 
their carts and carried the decaying shellfish to spread over their inland 
farms. The next step in the popularization of the scallop was made by 
the domestic animals, such as cats, dogs, pigs, etc., as the inhabitants 
let the swine obtain their living from the flats and shellfish. No records 
have been found by the writer to show that the Indians taught the 
colonists the use of the scallop as an article of food, or that they were 
conversant with its use for that purpose in England. So in all proba- 
bility the edible qualities of this mollusk gradually became known. 

Previous to 1874 the industry was of little importance as the scallops 
were only gathered by hand or taken from the shallow water with dip 
nets and rakes. This date marks the introduction of the dredge on Cape 
Cod, which revolutionized the industry by opening new territory and 
increasing the ease of capture in the deep water. From this time the 
fishery steadily increased and the market correspondingly widened. 

In Buzzard's Bay the fishery first started at New Bedford in the 
Acushnet River in 1870, furnishing between 1870 and 1879 a winter 
living for 15 men. From this locality the fishery spread rapidly in 1879 



106 THE SCALLOP FISHERY 

among the other shore towns on the north side of the bay. In 1879 
several boats from New Bedford commenced dredging in Wareham 
waters, and the townspeople soon followed the example of the invaders. 
From 1879 to 1899 the fishery became of importance as a winter industry 
in the upjDer waters of the bay, and flourished until 1899, when it became 
commercially extinct except at New Bedford and Fairhaven. The fall 
of 1907 furnished a revival of the fishery, which has every indication 
of becoming permanent. 

The industry first started on Cape Cod at Hyannis in 1874, where a 
number of men entered the new business; and for several years the 
production increased rapidly, with the opening of new territory and 
improved methods of cajDture. The other towns on the south side of the 
Cape entered in the new fishery at the same time and with similar 
success. From that time on the fishery has been a variable factor in 
the towns of this section, depending upon the supply. 

On the islands the fishery began at Edgartown in 1875 and at Nan- 
tucket in 1883, and in both cases the supply has been fairly constant, a 
poor or successful season depending more on the market price and the 
abundance in the rest of the State than on the local supply. 

While the natural supply has remained the same or has evidenced a 
decline in certain localities, the value of the industry as a whole, both 
in regard to the number of men engaged, capital invested and the market 
returns, has steadily increased. The price of scallops varies from year 
to year and at different parts of the same season; but in spite of the 
irregularity of the catch the price per gallon has increased threefold 
(from 50 cents to $1.50) since 1880, showing the increasing importance 
of the fishery. 

The Decline. 

The most important questions which first come to mind when consid- 
ering the scallop industry of to-day are these: (1) Has there been any 
decline in the industry? If so, how extensive? (2) What are the causes 
of the decline? 

Extent of the Decline. — There is no question but that the industry 
as a whole has declined. This decline has made itself manifest, espe- 
cially in certain localities, e.g., Buzzard's Bay, where until 1907 the 
entire fisherj'-, except at New Bedford and Fairhaven, had been extinct 
for seven years. Along the south side of Cape Cod, at Edgartown and 
Nantucket, the supply has, on the average, remained the same. Of 
course there is varying abundance each year, but as a whole the industry 
in these localities can hardly be said to have declined. On the other 
hand, on the north side of Cape Cod we find a noticeable decline. A 
scallop fishery no longer exists at PljTnouth, Barnstable harbor, Wellfleet 
and Provincetown, though twentj'-five years ago these places possessed 
a slight industry. 

So we have to-day in Massachusetts three localities, two of which show 



OF MASSACHUSETTS. 107 

a marked decline in the scallop fishery, while the other shows some im- 
provement. Of the two depleted areas, the one (north of the Cape) 
may never revive the industry; the other (Buzzard's Bay) gives indica- 
tions that the industry can once more be put on a profitable footing. 
The only thing necessary is perpetual precaution on the part of the 
fishermen in order to prevent this decline. 

Causes of the Decline. — The causes of the decline of this industry 
can be grouped under three heads : (1) natural enemies; (2) overfishing 
by man; (3) adverse physical conditions. In the last instance the 
severe winters, storms, anchor frost, etc., bring destruction upon the 
scallops, especially during early life. 

The Fishery. 

The Season. — There is considerable diversity of opinion among the 
scallopers as to when the scallop season should open. Some advocate 
November 1 as the opening date, instead of October 1, as the present 
law reads ; and many arguments are put forth by both sides. 

The class of fishermen who desire November 1 are those who are 
engaged in other fishing during the month of October, and either have 
to give it up or lose the first month of scalloping. Naturally, they wish 
a change, putting forth the additional argument of better prices if 
the season begins later. The scalloper who is not engaged in other 
fishing of course desires the law to remain as it is at the present time, 
claiming that the better weather of October gives easier work, more 
working days, and allows no chance of loss if the winter is severe. 

Under the present law, the town can regulate the opening of its 
season to suit the demands of the market and the desire of the in- 
habitants. This does away with the necessity of any State law on this 
point, which, under the present system of town control, would be 
inadvisable. 

The general opinion of the fishermen is in favor of the present date, 
October 1. As nearly as could be determined, about 75 per cent, favor 
October 1 and 25 per cent. November 1. This sentiment is divided by 
localities, as more men were in favor of November 1 at Nantucket 
and Edgartown than on Cape Cod and Buzzard's Bay, where very few 
favored a change. 

The Methods. — The methods of scalloping follow the historical 
rise of the fishery. As the industry grew more and more important, 
improvements became necessary in the methods of capture, and thus, 
parallel with the development of the industry, we can trace a corre- 
sponding development in the implements used in the capture of the 
scallop. 

(a) Gathering by Hand. — When the scallop was first used as an 
article of food, the primitive method of gathering this bivalve by hand 
was used. This method still exists on the flats of Brewster, and often 



108 THE SCALLOP FISHERY 

in other localities after heavy gales wagons can be driven to the beach 
and loaded with the scallops which have been blown ashore. 

(&) Scoop Nets The hand method was not rapid enough for the 

enterprising seallopers, and the next step in the industry was the use 
of scoop nets, about 8 inches in diameter, by which the scallops could 
be picked up in the water. These nets were attached to poles of vari- 
ous lengths, suitable to the depth of water. " This method," writes 
Ingersoll (8), "was speedily condemned, however, because it could be 
employed only where scallops are a foot thick and inches in leng"th, 
as one fisherman expressed it." 

(c) The Pusher. — The next invention was the so-called "pusher." 
The " pusher " consists of a wooden pole from 8 to 9 feet long, at- 
tached to a rectangular iron frame 3 by 1% feet, upon which is fitted 
a netting bag 3 feet in depth. The scalloper, wading on the flats 
at low tide, gathers the scallops by shoving' the " pusher " among the 
eel grass. When the bag is full, the contents are emptied into the dory 
and the process repeated. The seallopers Avho use the " pusher " go 
in dories, which are taken to the various parts of the scalloping ground 
and moved whenever the immediate locality is exhausted. This method 
is in use to-day, but is applicable only to shallow flats, and can be 
worked only at low tide, Avhere dredging is impossible. It is hard 
work, and not as profitable as the better method of dredging. This 
method of scalloping is used chiefly at Chatham, Dennis and Yar- 
mouth; occasionally at Nantucket and other towns. 

(d) Dredging. — The greater part of the scallop catch is taken by 
dredging, which is the most universal as well as the most profitable 
method. The dredge, commonly pronounced " drudge," consists of 
an iron framework about 3 by 1^ feet, with a netting bag attached, 
which will hold from one to two bushels of scallops. Catboats, carry- 
ing from 6 to 10 dredges, are used for this method of scalloping. These 
boats, with several " reefs," cross the scallop grounds pulling the 
dredges, which hold the boat steady in her course. A single run with 
all the dredges overboard is called a " drift." The contents of all 
the dredges is said to be the result or catch of the " drift." 

When the dredges are hauled in they are emptied on what is known 
as a culling board. This board runs the width of the boat, projecting 
slightly on both sides. It is 3 feet wide, and has a guide 3 inches 
high along each side, leaving the ends open. The scallops are then 
separated from the rubbish, such as seaweed, shells, mud, etc., while 
the refuse and seed scallops are thrown overboard by merely pushing 
them off the end of the board. Each catch is culled out while the dredges 
are being pulled along on the back " drift," and the board is again 
clear for the next catch. The culled scallops are first put in buckets 
and later transferred either to bushel bags or dumped into the cockpit 
of the boat. 



OF MASSACHUSETTS. 109 

Two men are usually required to tend from 6 to 8 dredges in a large 
eatboat, but often one man alone does all the work. This seems to 
be confined to localities, as at Nantucket nearly all the catboats have 
two men. At Edgartown the reverse is true, one man to the boat, 
though in power dredging two men are always used. 

Several styles of dredges are used in scalloping, as each locality has 
its own special kind, which is best adapted to the scalloping bottom 
of that region. Four different styles are used in Massachusetts, two of 
which permit a subdiAdsion, making in all six different forms. Each 
of these dredges is said by the scallopers using them to be the best; 
but for all-round work the " scraper " seems the most popular. 

(1) The Chatham or Box Dredge. — As this dredge was first used in 
Chatham, the name of the town was given to it to distinguish it from 
the other styles. At the present time its use is confined to Chatham and 
the neighboring towns of the Cape. With the exception of a very few 
used at Nantucket, it is not found elsewhere in Massachusetts. 

The style of the box dredge is peculiar, consisting of a rectangular 
framework, 27 by 12 inches, of flat iron 1 by %^ inches, with an oval- 
shaped iron bar extending back as a support for the netting bag, which 
is attached to the rectangular frame. To the side of the rectangular 
frame is attached a heavy ii-on chain about 4 feet long, to which is 
fastened the drag rope. 

(2) The Scraper. — As can be seen by the illustration, this style 
of dredge consists of a rigid iron frame of triangular shape, which 
has a curve of nearly 90° at the base, to form the bowl of the dredge. 
Above, a raised crossbar connects the two arms, while at the bottom 
of the dredge a strip of iron 2 inches wide extends from arm to arm. 
This strip acts as a scraping blade, and is set at an angle so as to dig 
into the bottom. The top of the net is fastened to the raised crossbar 
and the lower part to the blade. 

The usual dimensions of the dredge are: arms, 2^ feet; upper 
crossbar, 2 feet ; blade, 2^/2 feet. The net varies in size, usually holding 
about a bushel of scallops, and running from 2 to 3 feet in length. 
Additional weights can be put on the crossbar when the scalloper 
desires the dredge to scrape deeper. A wooden bar, 2 feet long, buoys 
the net. 

Two styles of this dredge are in use. At Nantucket the whole net 
is made of twine, while at Edgartown and in Buzzard's Bay the lower 
part of the net is formed of a netting of iron rings, the upper half 
of the net being twine. The iron rings are supposed to stand the wear 
better than the twine netting. This difference seems to be merely a 
matter of local choice. The " scraper " is perhaps the dredge most 
generally used, as, no matter what style is in use, a scalloper generally 
has a few " scrapers " among his dredges. 

(3) The "Slider." — The principle of the "slider" is the reverse 



no 



THE SCALLOP FISHERY 



of the '*' scraper," as the blade is set either level or with an upward 
incline, so the dredge can slide over the bottom. This dredge is used 
on rough bottom and in places where there is little eel gTass. In some 
dredges the blade is rigid, but in the majority the blade hangs loose. 

The " slider " used at Edgartown differs from the " scraper " by hav- 
ing" perfectly straight arms and no curved bowl, the blade being 
fastened to the arms in a hook-and-eye fashion. The dimensions of 
this dredge are the same as those of the " scraper," although occa- 
sionally smaller dredges are found. 

(4) The " Roller " Dredge. — This stjde of dredge is used only in the 
town of Mattapoisett, where the scallopers claim it is the most success- 
ful. The dredge is suitable for scalloping over rough ground, as the 
blade of the dredge is merely a line of leads, which roll over the surface 
of the ground gathering in the scallops. 

The dredge consists of an oval iron frame, 32 by 20 inches, which 
acts as the arms, and is attached to another iron frame, 32 by 3 inches. 
The blade of the dredge consists of a thin rope with attached leads. 
The net is made wholly of twine, and is about 2^2 feet long. 

Outfit of a Scalloper. — The average invested capital of the sealloper 
can best be givdn for two classes, — the boat fisherman and the dory 
fisherman : — 



Boat Fisherman. 



Boat, . 
Dory, . 
Six dredges, 
Rope and gear, 
Culling board, 
Incidentals, . 
Shanty, 

Total, . 



$500 00 
20 00 
25 00 
25 00 

2 00 

3 00 
50 00 



$625 00 





Dory 


Fisherman. 




Dory, . 






$20 00 


Oars, 


. 




1 50 


Pusher, 


. 


. 


2 50 


Shanty, 






25 00 



Total, 



$49 00 



Scalloping with Power Boats. — The season of 1907 has witnessed 
in Massachusetts the first use of auxiliary power in the scallop fishery. 
At EdgartoAvn the main part of the scalloping is now done by power, 
which, in spite of the additional expense of 5 gallons of gasolene per 
day, gives a proportionately larger catch of scallops. The Edgartown 
scallopers claim that their daily catch, using power, is from one-third 
to one-half better than under the old method of dredging by sail. Not 
only can they scallop when the wind is too light or too heavy for suc- 
cessful scalloping by sail, but more " drifts " can be made in the same 
time. A slight disadvantage of scalloping with power is the necessity 
of having two men, as the steering of the power boat demands much 
closer attention than the sail boat, which is practically held to a fixed 
course by the dredges. A power boat for scalloping possesses only the 



OF MASSACHUSETTS. Ill 

disadvantage of additional cost ; but it is only necessary to look forward 
a few years, when expedition rather than cheapness will be in demand, 
to a partial revolution in the present methods of scalloping, whereby 
the auxiliary catboat will take the place of the sail boat in the scallop 
fishery. 

Preparing the Scallop for Market, (a) The "Eye." — The edible 
part of the scallop is the large adductor muscle. The rest of the animal 
is thrown away, though in certain localities it is used as fish bait and in 
others for fertilizer. Why the whole of the animal is not eaten is hard 
to say. Undoubtedly aU is good, but popular prejudice, which molds 
opinion, has decreed that it is bad, so it is not used as food. This is 
perhaps due to the highly pigmented and colored portions of the animal. 
Nevertheless, there is a decided possibility that in the future we shall 
eat the entire scallop, as well as the luscious adductor muscle. 

The adductor muscle is called by the dealers and fishermen the " eye," 
a name given perhaps from its important position in the animal, and its 
appearance. The color of the " eye," which has a cylindrical form, is 
a yellowish white. 

(&) The Shanties. — The catch of scallops is carried to the shanty 
of the fisherman, and there opened. These shanties are usually grouped 
on the dock, so the catch can be readily transferred. Inside of these 
shanties, usually 20 by 10 feet or larger, we find a large bench 3 
to 3^ feet wide, running the length of the shanty, and a little more 
than waist high. On these benches the scallops are dumped from the 
baskets or bags, and pass through the hands of the openers. Under 
the bench are barrels for the shells and refuse. 

(c) The Openers. — The openers are usually men and boys, though 
occasionally a few women try their hand at the work. Of late years 
there has been a difficulty in obtaining sufficient openers, and the scal- 
lopers often are forced to open their own scallops. The openers are 
paid from 20 to 30 cents per gallon, according to the size of the 
scallops. One bushel of average scallops will open 2V2 to 3 quarts 
of " eyes." An opener can often open 8 to 10 gallons in a day, making 
an excellent day's work. The price now paid is more than double that 
paid in 1880, which was 12^2 cents per gallon. Some openers are 
especially rapid, and their deft movements cause a continual dropping 
of shells in the barrel and " eyes " in the gallon measure. 

{d) Method of opening the Scallop. — The opening of a scallop re- 
qiiires three movements. A flat piece of steel with a sharp but rounded 
end, inserted in a wooden handle, answers for a knife. The scallop 
is taken by a right-handed ojDener in the palm of the left hand, the 
hinge-line farthest away from the body, the scallop in its natural rest- 
ing position, the right or smooth valve down. The knife is inserted 
between the valves on the right-hand side. An upward turn with a cut- 
ting motion is given, severing the " eye " from the upper valve, while 



112 THE SCALLOP FISHERY 

a flirt at the same moment throws back the ujDper shell. The second 
motion tears the soft rim and visceral mass of the scallop and easts 
it into the barrel, leaving the " eye " standing clear. A third move- 
ment separates the " ej'^e " from the shell and casts it into a gallon 
measure. Frequently the last two movements are slightly different. 
The faster openers at the second motion merely tear off enough of the 
rim to allow the se^Daration of the " eye " from the shell, and on the 
third movement cast the " eye " in the measure, while the shell with 
its adhering soft parts is thrown into the refuse barrel. These last 
two motions can hardly be separated, so quickly are they accomplished. 

(e) Shipment. — The kegs in which the scalloi^s are shipped cost 
30 cents apiece, and contain about 7 gallons. A full keg is known 
as a " package." The butter tubs are less expensive, but hold only 
4 to 5 gallons. Indeed, anything which will hold scallops for shipment 
is used to send them to market. 

When the scallops get to the market they are strained and weighed, 
9 pounds being considered the weight of a gallon of meats. In this 
way about 6 gallons are realized from every 7-gallon keg. With the 
improved methods of modern times scallops can be shipped far west 
or be held for months in cold storage, for which purpose unsoaked 
scallops are required. Certain firms have tried this method of keeping 
the catch until prices were high, but it has not been especially suc- 
cessful. 

(/) Market. — One of the greatest trials to the scallop fisherman 
is the uncertainty of market returns when shipping. He does not 
know the price he is to receive ; and, as the price depends on the supply 
on the market, he may receive high wages or he may get scarcely any- 
thing. The wholesale market alone can regulate the price,' and the 
fisherman is jjowerless. While this is hard on the sealloper, it does 
not appear that at the present time anything can be done to remedy 
the uncertainty of return. The scallop returns from the New York 
market are usually higher than from the Boston market. The result 
of this has been to give New York each year the greater jDart of the 
scallop trade, and practically all the Nantucket and Edgartown scallops 
are shipped to New York. 

Either from a feeling of loyalty, or because the market returns are 
sooner forwarded, or because the express charges are less, Cape Cod 
still ships to the Boston market, in spite of the better prices offered 
in New York. Why so many Cape seallopers should continue to ship 
to Boston, and resist the attractions of better prices, is impossible to 
determine, and appears to be only a question of custom. 

{g) The Price. — The price of scallops varies with the supplj'. The 
demand is fairly constant, showing a slight but decided increase each 
year. On the other hand, the supply is irregular, some years scallops 
being plentiful, in other years scarce. 



OF MASSACHUSETTS. 



113 



The Food Value of the Scallop. 

The large adductor muscle is the only part of the scallop which is 
used for food at the present day, as the rest of the soft parts are con- 
sidered non-edible. The adductor muscle occupies the center of the 
shell and by reason of its conspicuous position has been given the name 
of " eye " by the fishermen. Less frequently it is spoken of as the 
" heart." From the standpoint of the consumer and the retail dealer the 
" eye '' is the object of imjDortance, and the word scallop is applied in 
such a way that many peoj)le believe that the little white cube comprises 
the whole animal. The " eye " can best be likened to the finished product 
of manufacture as it passes into the purchaser's hands. Therefore, it 
is to the advantage of the consumer to know (1) the amount of nutri- 
ment of the scallop compared with other articles of food, both shellfish 
and meats; (2) the effects of "soaking" scallops; (3) the amount of 
waste and the percentage of actual food in scallops from the different 
localities in the Commonwealth. 

Food Value. — As a food the scallop stands ahead of all the other 
shellfish, containing much more nourishment than the oyster. The fol- 
lowing figures are from the tables of Professor Atwater, rearranged by 
C. F. Langworthy (14) : — 





a" • 

i? 

r. (J) 
go 

o u 


1 

u 

1 


1 

o 


4J 

u 

1 


a 
1 


u 
a 

g 

%i 

SO 

o 


P-i_ 
1 
1. 


a 

it 


1^ 


Oysters, solids, 


- 


- 


88.3 


6.1 


1.4 


3.3 


.9 


11.7 


235 


Oysters, in shell, 


82.3 


- 


15.4 


1.1 


.2 


.6 


.4 


2.3 


40 


Oysters, canned, 


- 


- 


85.3 


7.4 


2.1 


3.9 


1.3 


14.7 


300 


Scallops, .... 


- 


- 


80.3 


14.7 


.2 


3.4 


1.4 


19.7 


345 


Soft clams, in shell, . 


43.6 


- 


48.4 


4.8 


.6 


1.1 


1.5 


8.0 


135 


Soft clams, canned. 


- 


- 


84.5 


9.0 


1.3 


2.9 


2.3 


15.5 


275 


Quahaugs, removed from 

shell. 
Quahaugs, in shell, . 


- 


- 


80.8 


10.6 


1.1 


5.2 


2.3 


19.2 


340 


68.3 


- 


27.3 


2.1 


.1 


1.3 


.9 


4.4 


65 


Quahaugs, canned, . 


- 


- 


83.0 


10.4 


.8 


3.0 


2.8 


17.0 


285 


Mussels 


49.3 


- 


42.7 


4.4 


.5 


2.1 


1.0 


8.0 


140 


General average of mol- 
lusks (exclusive of 
canned) . 


60.2 


- 


34.0 


3.2 


.4 


1.3 


.9 


5.8 


100 



In the following table the scallop is compared with the chemical 
analysis of various meats in their food stuffs. The figures for the meats 



114 



THE SCALLOP FISHERY 



are taken from Howell's "Physiology" (13). The comparative prices 
were obtained in the Boston markets on Feb. 18, 1910. 





In 100 Parts (Per Cent.). 


Wholesale 

Price 
per Pound 

(Cents). 




Water. 


Protein. 


Fat. 


Carbo- 
hydrate. 


Ash. 


Scallop "eyes," 
Beef, moderately fat, 

Veal, fat 

Mutton, moderately fat, . 
Pork, lean 


80.30 
73.03 
72.31 
75.99 
72.. ')7 


14.70 
20.96 
18.88 
17.11 
20.05 


.20 
5.41 
7.41 
5.77 
6.81 


3.40 
.46 

.07 


1.40 
1.14 
1.33 
1.33 
1.10 


191/2 
88/4 
121/2 
10 
14% 



'' Soaking." — The " eye " is frequently put through a process famil- 
iarly known as " soaking " before it is sent to market. If not done 
by the fishermen it is completed by the dealer, in order to tempt the 
purchaser with a beautiful white, plump " eye " instead of a small 
yellow-colored sjoecimen. Undoubtedly fishermen and dealers would 
willingly sell unsoaked scallops at a projDortionate price the moment the 
market demands them; but the consumer, through ignorance, prefers the 
large, nice-appearing " eyes," and thus unwittingly favors the practice. 

From a practical standpoint " soaking " is a very simple affair, the 
" eyes " being placed in fresh water for several hours until they have 
absorbed sufficient water to increase their bulk about one-third. It has 
been noticed that whenever salt-water products are allowed to soak in 
fresh Avater an increase of bulk is found. This is due to a complicated 
change, the most prominent factor being osmosis, which causes a swell- 
ing of the tissues. The " eye " can be increased by this change to a gain 
of more than one-third its natural size; that is, 4^/2 gallons can be in- 
creased to 7 by judicious " feeding " with fresh water. 

Two methods of swelling scallops are in use. When the scallops are 
shii:)ped in kegs which usually contain 7 gallons, the following method 
is applied : 4^2 to 5 gallons of " eyes " are placed in each keg, and are 
allowed to stand over night in fresh water; in the morning, before ship- 
ment, more water is added and the keg closed, and by the time of arrival 
to the New York or Boston market the scallops have increased to the 
full amount of 7 gallons. The second method of " soaking " is slightly 
more elaborate. The " eyes " are spread evenly in shallow wooden sinks, 
5 by 3 feet, with just enough fresh water to cover them, and left over 
night. In the morning a milky fluid is drawn off, and the " soaked " 
scallops are packed for market in kegs or butter tubs. 

The process of " soaking " was not instituted until some years after 
the start of the scallop industry. In 1886 Ingersoll (8) reports that 
scallops were not being " soaked " in Khode Island and Connecticut. 
Dr. Hugh M. Smith (12) attributes the beginning of soaking to the fact 



OF MASSACHUSETTS. 115 

that the small Cape scallops could not compete in the Boston market 
Avith the larger Maine scallops (deep sea), and that the fishermen found 
it necessary to increase the size by swelling. If this were the cause, 
the fishermen soon found it decidedly to their advantage to continue the 
process of selling " watered stock." 

A change has taken place in the appearance of the scallop a few 
hours after soaking. The small yellow or pinkish " eye " of the freshly 
opened scallop has taken on a white, plump appearance, adding greatly 
to its salable qualities. On the other hand, the fine flavor and freshness 
have disapiDeared, " soaked " out, so to speak, and the transformed scal- 
lop lacks many of the qualities which endear it to the heart of the 
epicurean. Considerable loss in nourishment has taken place, although 
exact figures have not been conclusively obtained by experiment, and 
the scallop spoils much sooner than the unsoaked. If kept too long 
the absorbed water is given ofi" and the scallop shrinks back to its 
original size, a process which is more quickly accomplished on the 
frying pan, where the " soaked " scallop rapidly shrivels. While too 
much cannot be said to discourage the " soaking " of scallops and to 
educate the public to demand the real article, it can be fairly stated 
that the process, although producing an inferior article of food, is not 
detrimental to the public health as long as proper sanitary precautions 
are taken by having the surroundings hygienic and by using pure 
water. 

The practice of " soaking " Avill only come to an end when the public 
refuse to buy anything but " dry " scallops, and only till then, unless 
special legislation is enforced, will " soaked " scallops be taken from 
the market. At the present time, if the wholesale dealers uniformly 
demanded " unsoaked " scallops from the fishermen, and increased the 
price, they would be able to get their shellfish unsoaked. 

Food and Waste. — The determination of the amount of food and 
waste in the scallop was undertaken with scallops from six scalloping 
towns, comprising the three sections of Buzzard's Baj'-, Cape Cod and 
the islands. In this work the " eye " w^as considered the only edible 
part of the animal. Four sizes, 55 millimeters, 60 millimeters, 70 milli- 
meters and 75 millimeters were used. Ten scallops of each size were 
dissected, and the weight of the different parts recorded. 

(a) The Food Value of the Average Scallop.' — The "eye" or edible 
portion constitutes but a small part of the entire scallop. By weight 
the actual food in a scallop of 65 millimeters (2%c inches), the average 
from all the determinations, is only 17.77 per cent, of its weight. Thus, 
in order to get 18 pounds of " ej^es " (2 gallons) it would be necessary 
to procure 100 pounds of living scallops. 

The average scallop (Fig. 82) is made up as follows: total weight, 
1.5 ounces, or 100 per cent. ; total non-edible part, 1.23 ounces, or 82.23 
per cent, (includes both shell and non-edible soft part) ; non-edible soft 



116 THE SCALLOP FISHERY 

parts, .49 of an ounce, or 32.8 per cent. ; shell, .74 of an ounce, or 49.43 
per cent.; actual food, .27 of an ounce, or 17.77 per cent. Considering 
merely the soft parts of the scallop, the proportion of food and waste 
is much closer. The '' eye " is by weight 35 per cent, of the soft parts, 
while the non-edible soft parts constitute the remaining 65 per cent. 

(b) The Non-edible Parts. — The non-edible parts of the scallop can 
be divided into two classes, (1) the shell or hard portion, which is neces- 
sarily waste except for certain uses common to all shellfish, (2) the 
viscera of the scallop, or all parts except the " eye." The latter is the 
non-edible part proper; as in other shellfish these parts are utilized for 
food. 

(1) The Shell. — The shell impregnated with lime salts necessarily 
makes mj) a good portion, about one-half, of the total weight. However, 
it cannot be considered waste except in a non-edible sense, as the scallop 
shell is found useful in several ways, (a) Oyster planters buy large 
quantities of shells for eultch to catch the oyster set, as the fragile 
nature is most serviceable in separating the clusters of young oysters. 
The average price runs from 3 to 5 cents per bushel. The greater part 
of the shell heaps are utilized for this purpose, {b) On Cape Cod, 
shell roads and walks are sometimes made with scallop shells, (c) Work 
baskets, pin cushions and various ornaments of the house are decorated 
with scallop shells, {d) Within the last few years scallop shells bound 
together with ribbon and containing miniature photographic views, for 
souvenir postal cards, have been put on the market by Boston firms, who 
purchased the cleaned shells from the scallojoers at the rate of $6 jDer 
barrel. Only the lower or bright colored valve is used. 

(2) The Soft Parts. — The non-edible part or body of the scallop 
forms 32.8 per cent, by weight of the total scallop. While not utiUzed 
for food at the present time, although there is no reasonable objection 
except custom and prejudice, it is made use of for {a) fish bait, either 
fresh or salted; (£•) fertilizer. The probable reason why this whole- 
some flesh is not made use of as food is because of the brilliant coloring 
of the mantle and its tough apj)earance. Other shellfish, such as the 
clam, quahaug and oyster, are eaten entire, and there is no good reason 
why the scallop should not be taken in the same way, 

(c) The Size of the " Eye." — The relative size of the " eye " increases 
with the size of the scallop, as its percentage by weight is slightly 
greater in large scallops. The percentage by weight for a 60-millimeter 
scallop is 17.47 per cent.; for a 65 -millimeter, 17,87 per cent.; for a 
70-millimeter, 17,97 per cent., while the ratio of shell and body does not 
seem to change. The actual weight of the " eye " varies in the different 
localities, some showing as much as one-fourth more weight for the 
same sized scallop. In percentage the Buzzard's Bay district led, averag- 
ing about 18.18 per cent., with 18.70 per cent, high at New Bedford, 
while Chatham and Nantucket gave only 17,20 per cent, and 16.67 per 



OF MASSACHUSETTS. 117 

cent, respectively. This fact does not indicate anything about the 
food vahie of the scallops from these localities, but is merely cited to 
show the variation in the weight of the " eye/' and that Buzzard's Bay 
scallops should yield a greater return per bushel. Beside this variation, 
two conditions influence the size and weight of the "eye": (1) the sea- 
son or time of year, as the " eye " is reported by the fishermen " to turn 
out more to the bushel" when the cold weather comes on; (2) the age 
of the scallop, as the "eye" of a two-year-old scallop (one that has 
passed the period of allotted life) is looser in texture and weighs less. 
(d) Weight of Shell. — Differences in the weight of the shell for 
scallops of the same size occur in different localities. The weight of the 
shell is determined by two factors, (1) the rapidity of growth; (2) the 
amount of lime salts in the water. These factors are rarely the same 
for any two localities, and naturally variations would be expected in 
the weight of the shell. The average weight of the shell for a 65-milli- 
meter scallop is 21.9 grams, yet in six localities we find the weights 
ranging anywhere between 20 and 23 grams. 

The Laws. 

The question of scallop legislation has attained considerable impor- 
tance during the past four years, particularly in regard to the " seed " 
scallop. During this period three laws have been passed, with the 
ostensible purpose of protecting the " seed," but have proved far from 
satisfactory both from the standpoint of the fishermen and the officials 
employed by State and towns for their enforcement. The reasons for 
the unsatisfactory state of affairs resulting from this frequent change in 
legislation are twofold: (1) it is almost impossible to give a compre- 
hensive legal definition of a "seed" scallop; (2) a general law neces- 
sarily cannot suit all localities. The present law of 1910, founded on 
the legislative experience of past years, should prove satisfactory to the 
State as a whole. 

In the early days the scallop was not considered worthy of legisla- 
tion, as it had no market value, and was generally considered as a 
poisonous or non-edible shellfish. With the opening of the market 
arose the necessity of regulating the fishery, and legislation of a restric- 
tive character was enacted. 

Previous to 1874 the scallop came under the general acts included in 
the term shellfish, with the clam, oyster and quahaug. The general 
acts were of several kinds, (1) town regnilation ; (2) permits; (3) seizure 
in vessels; and (4) protection of the shellfisheries by limiting the catch, 
place and time of taking. 

In 1874 occurs the first mention of the word scallop in a legislative 
act " to regulate the shellfisheries in the waters of Mount Hope Bay 
and its tributaries," whereby the selectmen of the towns bordering on 
Mount Hope Bay were permitted to grant licenses for the cultivation 



118 THE SCALLOP FISHERY 

of clams, quahaugs and scallops, and other shellfish to any inhabitant. 
It seems strange that such an advanced and beneficial act should have 
been passed at that early period, as it was clearly before its time, and 
unsatisfactory, as is shown by its repeal the following year. It is only 
within the last year that similar legislation has been passed for the 
quahaug. Although it is improbable that the cultivation of scallops will 
ever become extensive, it is only the question of a short time when the 
cultivation of all shellfish will be legalized. 

The second mention of the word scallop is found in the act of 1880, 
by which the Commonwealth gave to the towns and cities their present 
oversight of the shellfisheries and full power " to control and regulate 
the taking of eels, clams, quahaugs and scallops." This act was later 
amended by the Acts of 1889, but the general terms of the act were 
not changed, and the present law is but slightly different. Town con- 
trol as applied to scallop fishery has its advantages and disadvantages, 
and the wisdom of State control is a debatable question. The present 
system is to the advantage of certain towns and a loss to the fishermen 
of the other toAvns and to the general consumer, since town restrictions 
prohibit the taking of shellfish by outsiders. Owing to the short life of 
the scallop the adults left untaken, occasionally in large numbers at the 
end of a season, perish before another year. More men could have 
been given employment and a greater supply furnished the consumer 
if the large beds had been opened to other fishermen besides townsmen. 
As matters exist, the majority of fishermen seem satisfied with the 
present system of town control, and until public opinion is favorable 
to the best utilization of the scallop fishery, State control is not desirable. 

Special legislation for the scallop fishery was first enacted in 1885 
by an act which limited the catch to 25 bushels a boat per day, the 
first restrictive legislation upon the scallop fishery. Since that time, 
within twenty-six years, eight State and seven special acts for towns, 
in all fifteen laws, have been enacted, all but one of which have been for 
the regulation of the fishery as regards permits, season, catch and town 
supervision. The only exception was an act empowering the Commis- 
sioners on Fisheries and Game to make an investigation of the spawn- 
ing and propagation of the scallop. These laws illustrate the following 
features : — 

Daily Limit to the Catcli. — The act of 1885 placed a limit of 25 
bushels per day for each boat, making no allowance as to the size of 
the boat. No record of the repeal of this act has been found, and it 
remained practically an unknown law until 1910, when a limit of 10 
bushels per day for each person was passed. 

The Season.. — Previous to the act of 1885, which made a closed season 
between April 15 and September 1, there had been no restriction upon 
the time of capture. The primary object of this act Avas due to a desire 
to protect the scallop during its breeding season, and because the winter 



OF MASSACHUSETTS. 119 

months were the best suited for handling and marketing the " eyes." 
In 1887 and in 1896 the closed season was changed to April 1 to Octo- 
ber 1, which proved satisfactory until 1909, when the experiment was 
tx'ied of shortening it to September 1. In 1910 the act of 1909 was 
repealed, at the petition of the scallop fishermen of the Commonwealth, 
and the old limits (April 1 to October 1) resumed. The acts of 1885 
and 1887 prohibited the capture, sale and export of scallops during the 
closed season, while that of 1896 replaced the word export by " have 
in possession." In 1909 any inhabitant of the Commonwealth was per- 
mitted to gather by hand scallops for his own use at any season. 

The Penalties. — The acts of 1885 and 1887 gave a maximum penalty 
of $20, which was increased to $50 by the act of 1896, which likewise 
established a minimum of $20. The acts of 1907, 1909 and 1910 lowered 
this penalty to a minimum of $5 and a maximum of $20. Special acts 
for the towns of Buzzard's Bay, in 1888, 1892, 1893 and 1900, estab- 
lished a penalty of $20 to $100. 

" Seed " Scallops. — Legislation for the protection of the " seed " 
scallop was first enacted in 1887, with maximum penalty of $20 for 
each offence, which was increased to $50 in 1896. Neither act in any 
way defined the term " seed " scallop. In 1906 a " seed " scallop was 
legally defined as a scallop under 2 inches, but a size limit proved un- 
satisfactory, owing to the great variation in size of young and adult 
scallops, and was replaced in 1907 by a detailed definition. This defi- 
nition, although describing thoroughly the " seed " scallop, proved too 
cumbersome for legal use, and was simplified in 1909 to read merely 
'■' a well-defined growth line." The act of 1909 gave a leeway of 15 per 
cent, for the '' seed " unavoidably taken, which made the law difficult to 
enforce and harmful to the fishery. This percentage was lowered to a 
nominal 5 per cent, in 1910. " Seed " scallop legislation has been the 
most troublesome, owing to the difficulty in adequately defining the 
term so that it will bear legal interpretation. As long as the scallop 
fishermen refuse to take the immature scallops, there is but little need 
of the rigid enforcement of the " seed " scallop law. 

Town Laics. — Special acts for towns are somewhat different than 
the general State laws governing the fishery, as they merely apply to 
local waters and emphasize the powers already given by the general 
shellfish law of 1880 to the town officials. Special scallop laws apply 
to Nantucket, Wareham, Bourne, Marion, Rochester, Mattapoisett and 
Fairhaven, and are of two classes : — 

(a) Bait Regulation.- — Nantucket is the only town which is alloAved 
to catch scallops for bait out of season, and here only from April 1 
to May 15, according to an act of 1901, previous to which the limit 
was from April 1 to May 1 by the act of 1888. 

(&) Local Regulation by Permits. — The selectmen of the toAvns 
above mentioned, except Nantucket, were empowered by special acts to 



120 



THE SCALLOP FISHERY 



issue i^ermits for scalloping in whatever way they saw fit, and at what- 
ever charge they deemed proper. A severe penalty of $20 to $100 fine 
was imposed for taking scallops without permits, except for family use 
and for bait. At the present time five towns, Fairhaven, Marion, Matta- 
poisett, Wareham, and Nantucket, issue special scalloping permits, 
while four others. Bourne, Chatham, Edgartown and Harwich, include 
the scallojDS under the general shellfish permits. 

The local town laws which benefit the scallop industry are made each 
year according to the condition of the industry. Edgartown and Nan- 
tucket have i^erhaps the best-governed scallop industries. Laws requir- 
ing licenses, regulating the opening of the season and restricting at 
proi^er times the catch, so as to get the best market prices instead of 
overstocking the market when the prices are low, are to be recommended 
on account of their benefit to the scallopers. 



Scallop Legislation. 



No. 


Date. 


Kind. 


Penalty. 


Provisions. 


Remarks. 


1 


1874 


Special > 


$5 to $10 and $1 


License to plant scallops in 


Repealed 1875; 


^ 




town. 


per bushel. 


Somerset, Swansea, Fall 
River. 


word "scallop" 
mentioned. 


■^ 2 


1880 


State, . 


$3 to $50, . 


Towns to regulate shellflsh- 
eries. 


Word "scallop" 
mentioned. 


3 


1885 


. State, . 


$20, .- 


25 bushels limit; closed sea- 
son April 15 to September 1. 


- 


4 


1887 


State, . 


$20, 


Seed scallops; closed season 
April 1 to October 1. 


- - 


W. 5 


1887 


Town, . 


- 


Nantucket allowed to take 


- _ 










scallops for bait from 
April 1 to Rlay 1. 




6 


18S8 


Town, . 


$20 to $100, . 


Wareham and Bourne; per- 
mits. 


- 


7 


1889 


State, . 


- 


Town regulation, . 


Modification o f 
No. 2. 


8 


1892 


Town, . 


$20 to $100, . 


Marion, same as No. 6; per- 










mits. 




9 


1893 


Town, . 


" 


Marion, Sec. 4 of No. 8, 
amended; Rochester, Mat- 
tapoisett. 


Word "waters" 
added. 


10 


1893 


Town, . 


$20 to $100, . 


Fairhaven, same as No. 8, . 


- 


11 


1896 


State, . 


$20 to $50, . 


Seed prohibited ; season 
April 1 to October 1. 


Repetition of 1887 
act, except pen- 
alty. 


12 


1900 


Town, . 


$20 to $100, . 


Mattapoisett, same as No. 8, 


13 


1901 


Town, . 


- 


Nantucket; bait, April 1 to 

May 15. 
Capture prohibited in con- 


- 


14 


1901 


State, . 


$5 to $10 for first 


General shellfish; 








offence; $50 to 


taminated waters. 


Fish and Game 








$100. 




Commission 
powers. 


15 


1905 


State, . 


- 


Investigation and report, . 


- 


16 


1906 


State, . 


$20 to $50, . 


"Seed" scallop, 2-inch limit, 


Repealed, 1907. 


17 


1907 


State, . 


$5 to $20, . 


" Seed" scallop, definition, . 


Repealed, 1909. 


18 


1909 


State, . 


Not exceeding 

$25. 


Definition of "seed" scal- 
lop; 15 per cent. " seed "; 
capture by hand at any 
time. 


Repealed, 1910. 


19 


1910 


State, . 


Not exceeding 

$25. 


Definition of "seed" scal- 
lop; 5 per cent, "seed"; 
capture by hand at any 
time ; daily catch 10 bushels. 





OF MASSACHUSETTS. 121 



Method of Improving the Scallop Industry. 

At the present age a fishing industry must show a steady development 
to keep pace with the increasing market, which is continually widening 
through better transportation facilities. Unfortunately, the tendency 
in the past has been, particularly in industries directly dependent upon 
natural resources, to meet the question of progression by increasing the 
yield through the improvements in implements and methods rather 
than by attempts to increase the natural supply, with the result that 
under the increased strain the natural resources have been seriously 
impaired and oftentimes completely destroyed. In these cases protective 
legislation has either been absent or based upon wrong principles. Ex- 
amples of impaired resources are found in the natural oyster beds, the 
shad, sturgeon and alewife fisheries, the clam, quahaug and lobster 
industries, etc. In the future, fishing industries should be developed 
both by improved methods and by the increasing of the natural supply 
through propagation and protection, a work which is being carried on 
by federal and State fish commissions, and is gradually widening its 
scope to include all kinds of fisheries. 

The scallop fishery presents peculiarities which differentiate it from 
other fishing industries, and a knowledge of Avhieh is essential in con- 
sidering its improvement. (1) Protective legislation is principally 
confined to the " seed " scallop, or scallop less than one year old, 
although the new law of 1910 has placed a daily limit of 10 bushels for 
each man's catch. (2) The future welfare lies wholly in the hands of 
the fishermen and their proper respect for the jDreservation of the 
"seed" scallop. (3) Although there is plenty of room there is no 
great prospect for a wide expansion of the fishery, as there are few 
Avays of artificially increasing the supply; but, on the other hand, if the 
spirit of protective legislation prevails there is but slight danger of a 
serious diminution. (4) The scallop fishery is peculiarly fortunate, as, 
unlike the clam and quahaug industries, it is unaffected by heavy fish- 
ing and needs but minimum care on the part of the fishermen to remain 
in excellent condition for years to come. Thus, while there are few 
possibilities for its development by increasing the natural supply, 
there is but slight danger of its permanent extinction. 

Methods of Increasing the Natural Supply. — The possibilities of 
increasing the supply of scallops and thus improving the fishery will 
first be taken up. Many short-sighted fishermen would be opposed to 
the increasing of the supply, for they consider that the price would be 
lowered, and they would prefer a high price and small supply. But 
this idea is erroneous, as it takes no longer to dredge from thick beds 
than it does from depleted areas, and in view of the increasing popu- 
larity of the scallop the price would soon regain its former level. The 
consumer would be the gainer by the increased production, which would 



122 THE SCALLOP FISHERY 

tend to make scallops no longer a luxury but a part of the common 
diet. However, the fisherman need have no fears in this direction, as 
investigation has shown that there can be no great increase in the scallop 
supply, although many of the poor years can be avoided hj proper 
foresight and by work along the lines here suggested. 

The reason that the scallop supply can never be successfully increased 
is due, (1) to no practical means of artificial culture; (2) it was found 
by this department that money expended in propagating the embryos 
and young at the present time would be wasted, for the destructive 
agencies enumerated in chapter IV. would defeat any increase of the 
supply through successive years, one bad season undoing the work of 
several years and entailing a new start. If a severe winter killed all 
the spawning scalloj)S in one locality, there would be the same scarcity 
of spawn, no matter how great the number of scallops. If such disas- 
ters were of rare occurrence the effect would not be so important, but 
destruction often occurs upon the shallow flats. Thus, under natural 
conditions there seems a maximum and minimum point of variation 
between which the scallop supply is constantly wavering. The supply 
can be somewhat increased and conditions imjDroved by judicious trans- 
planting from tlie exposed places, thus eliminating the adverse con- 
ditions. 

(a) Artificial Propagation. — Artificial propagation may be of two 
kinds: (1) raising the young from the eggs; (2) catching the spat. So 
far our experiments have indicated that it is impossible to raise the 
3'^oung embryos in sufficient numbers for commercial hatching. Un- 
doubtedly some benefit would result from the artificial fertilization of 
the eggs and the liberation of the young larvae when they first begin to 
swim, as in nature there is a great loss through non-fertilization. But 
such a result is purely theoretical, as there is no way of determining 
the loss when the spawn is liberated. When kej^t in hatching tubs the 
majority die before they attain the shell stage. So far this method has 
proved unsatisfactory, and it is hardly believed that it can be put on a 
practical basis. 

Spat collecting has already been considered under chapter IV., and it 
onlj^ is necessary here to state that for practical work spat collecting 
does not pay, as greater quantities of scallops can be obtained when 
small from the eel-grass flats than could be caught with extensive spat- 
collecting apparatus. Looking at it in one Avay the scallop supply 
would be increased so much by the scallops taken on the collectors, 
as they probably would not survive to set elscAvhere, but such Avould 
be a " penny wise and pound foolish "' method for the planter. If a 
scallop culturist found it impossible to obtain " seed " it might pay him 
to try spat collecting. This would only occur in rare instances, where 
scallops were not jDlentiful. 

(b) Artificial Culture. — The question of raising scallops artificially 
for the market, and thus increasing the general supply, was one of the 



OF MASSACHUSETTS. 123 

first points considered in this investigation. Parallel work on the qua- 
haug and clam showed that by individual culture or farming the general 
supply could be increased, barren area made to yield a harvest, the 
decline of the natural supply checked, and a profitable industry employ- 
ing several times the number of men now engaged could be started. 
Conditions were found to be different with the scallop. There are serious 
limitations to individual cultivation. Scallops can swim and move for 
short distances, although they do not make the long migrations com- 
monly credited to that species, and thus require penning. It was found 
that in a few places in the State the scallop could be cultivated by 
private persons. In every instance the locality of the prospective 
grant was in a small bay with a narrow outlet, situations so rarely 
existing that the idea of private scallop culture must be abandoned. 
Undoubtedly in the future, when grants are given for oysters, clams 
and quahaugs, they will be assigned under the broad term of " shellfish 
grants," and the scallops upon these bottoms will be considered as be- 
longing to the grantee. In such cases the scallop is of secondary con- 
sideration, and in reality there will never be many true scallop grants. 

(c) Communal Culture. — The scallop offers better opportunities for 
communal culture, i.e., by towns. There is but one way now known of 
artificial propagation for the scallop industry, i.e., by transplanting 
in the fall the abundant set from the exposed places to the deeper 
water before the " seed " is killed by the Avinter. It is merely assisting 
nature by preventing a natural loss, and in no sense can properly be 
termed propagation. It is a preventive, and money used in this way 
to preserve the scallop is well expended. Usually the set is abundant, 
and can be transferred in large numbers. This is the only practical 
method now known of increasing our scallop supply, though it is 
hoped in the future that other methods may be devised. 

In connection with the above comes the question, if we can thus 
preserve scallops doomed to destruction, will it not be profitable to 
transplant scallops to places where the scalloping has been exterminated 
by various causes, and by means of these " seeders " furnish succeeding 
generations which may populate the barren areas'? This plan is prac- 
tical and feasible, and should be given due consideration. Why should 
not scallops be transplanted to the harbors of Buzzard's Bay to again 
restock these areas? Often the attempt might fail, but there is bound 
to be success if there is perseverance. The best time to plant scallops 
is in the fall, as a double service will be given: (1) preservation from 
destruction of the seed scallops; (2) furnishing spawn and young in 
the barren locality. IngersoU (8) speaks of the restocking of Oyster 
Bay in 1880 : — 

In the spring of 1880 eel grass came into the bay, bringing young scallops 
[the eel grass carries the scallops attached to it by the thread-like byssus] ; 
thus the abundance of that year was accounted for, though there had not 
been a crop before in that bay since 1874. 



124 THE SCALLOP FISHERY 

If sueli a restocking can be aeeomplislied by nature, it can be done 
with more certain effect with man's assistance. 

Restocking Barren Areas.. — The practicability of restocking barren 
or depopulated areas is illustrated by the following: As few natural 
scallops were found in the Powder Hole, Monomoy Point, in 1906, and 
as it was desired to have the place well stocked for experimental work 
in 1907, 50 bushels of small scallops about the size of a quarter of a 
dollar were transplanted from the Common Flats at Inward Point in 
November, 1906. The result was an enormous set from these " spawn- 
ers " in 1907, and the sandy bottom along the shores of the Powder Hole 
during the fall of 1907 and the summer of 1908 was thickly covered 
with the numerous 1907 set. The fishermen, who had been at Monomoy 
for years, remarked that it was the largest set that had ever been seen 
in the Powder Hole. It can be fairly asserted that the remarkable 
abundance was due to the bringing in of the spawners, and that this 
case is a striking illustration of the proper methods of assisting nature 
in increasing the scallop supply in any particular locality. 

Our present town laws stand as obstacles to any restocking, as no 
town will give up the slightest part of its " seed " scallops to another 
town, thus making any practical tests impossible. Time will smooth 
away these difficulties, and the welfare of the community as a whole will 
be placed before the petty rivalry of towns. 

Improving the Fishery. — The second means of improving the indus- 
try is to increase the efficiency of the fishery as regards methods, mar- 
keting, utilization of waste, etc. Perhaps the most important means of 
developing the fishery is to keep the fishermen well informed as to what 
is going on in other scalloping districts, what opportunities are being 
opened for the marketing of shellfish, how the waste products can be 
utilized, and how the fishery can be preserved. This report contains 
practically all obtainable information upon the scallop and the industry 
in Massachusetts at the present time. While the main facts set forth 
in the preceding pages about the life and habits of the scallop will 
remain the same, the condition of the industry will change, and in the 
future the descriptions of methods, implements, marketing, etc., will be 
of little i^ractieal value except from an historical standpoint. It is 
sincerely hoped that this report will attain its main object, i.e., the 
presentation of the life history of the scallop and the needs of the 
industry in such a light to the fisherman that he will realize the great 
necessity of the preservation of the " seed " scallop for the maintenance 
of the fishery. At regular intervals, for instance every five years, small 
pamphlets containing up-to-date information concerning methods of 
developing the fishery, as regards implements, marketing, utilization of 
waste, etc., should be distributed among the scallopers. 

Besides the utilization of the waste parts, the uses of which at the 
present time have been enumerated under the food value of the scallop, 



OF MASSACHUSETTS. 125 

the market can be improved in three Avays: (1) To do away with the 
marketing of '' soaked " scallops by the co-operation of the dealers 
and the payment of a proportional increase in price per gallon for 
"dry" scallops from the fisherman. (2) Co-operation between com- 
mission merchants and scallopers, which would result in better satisfac- 
tion in both goods and prices, and do away to some extent with that 
gTeat bugbear, " uncertainty of returns," which is so discouraging to 
the fisherman and makes the fishery a lottery. (3) To increase the 
popular demand for scalloj)s by wider fields through the transportation 
facilities and advertising. 

The methods of capture will slowly improve. No suggestions can be 
offered here for improvements in dredges, etc., as each locality has con- 
ditions peculiar to itself. The description of the different styles of 
dredges in the various localities may cause innovations in certain sec- 
tions which have fallen in that rut of custom so prevalent in our fishing 
towns. During the last few years the gasolene dredger has gradually 
replaced the sail, and while dredging with sail will probably remain, it 
will be in combination with power, as in power catboats, resulting in a 
partial revolution in scalloping methods. 

The question of just and fair laws has been an important factor in 
the fishery. While in the past all laws have not met this standard, the 
tendency at the present time and for the future is improvement in sim- 
plicity and justice, with the sole aim of preserving the fishery, serving 
the consumer and protecting the fisherman. 

CHAPTER VII — METHODS OP INVESTIGATION 

Owing to the different classes of readers, and with a desire to pre- 
sent the material so that it will be intelligible to all, it has seemed 
best to " cull " from the main portions of the report the various 
methods, tables, etc., which were used in its preparation, and to incor- 
porate them in a reference chapter, where, though accessible, they 
will not interfere with the continuity of the narrative. In this way 
the report is made more interesting to the fishermen and general pub- 
lie, without detracting from its scientific value. Throughout the paper 
constant reference is made to the contents of this chapter, for the 
purpose of avoiding repetition and unnecessary description. 

The chapter is mainly divided into: (1) methods used in obtain- 
ing the early embryology and life history; (2) methods of conducting 
the growth experiments; (3) tables; (4) glossary; and (5) bibliog- 



Emhryological Methods. 
It is hardly necessary to describe in detail the general method of 
investigation of the early life history of the scallop. It is sufficient to 
state that the usual methods of microscopic study, camera lucida 



126 THE SCALLOP FISHERY 

drawings, various miei'ometers, preparations, fixatives, etc., were em- 
ployed, while the material was obtained in a variety of ways, as is 
hereafter described. The investigation on the life history was car- 
ried on at Monomoy Point during the summers of 1906, 1907, 1908, 
and 1909, and at Wellfleet in 1908. Only those methods are here 
described which especially apply to the scallop or show some pecu- 
liarity which rendered them of value in this investigation. 

MetJwd of measuring the Scallop Egg. — The size of the mature 
scallop eggs was determined with the aid of camera lucida drawings 
and a standard stage micrometer. This work was done with oculars 
1 and 2 and objectives % and %, Bauseh and Lomb microscope, the 
camera lucida and stage micrometer also being obtained from the 
same firm. The average measurements of several batches of eggs, 
hatched in 1906 at Monomoy Point, just previous to fertilization, gave 
the long diameter as M5.58 millimeter (%96 of an inch) and the short 
diameter as %6.G6 millimeter (M23 of an inch). These measurements 
do not correspond with those made by Risser (2), who found the 
size to be %ooo of an inch, or about one-fifteenth as large as the meas- 
urements made in this investigation. 

Method of determining the Number of Eggs produced hy the Aver- 
age Scallop in One Season. - — How many eggs does a scallop contain 
at time of spawning? The answer varies with the size of the scallop, 
a large specimen possessing many times the number in a small one. 
For the purpose of determining two sizes were used, (1) small, 40 
millimeters (1% inches), (2) large, 68 millimeters (2% inches). Tak- 
ing %6 of a millimeter {}Aqo of an inch) as the average diameter of 
a scallop egg, the number of eggs in a cubic millimeter can be esti- 
mated as 4,096, and as there are 1,000 cubic millimeters to 1 cubic 
centimeter, there would be 4,096,000 eggs to 1 cubic centimeter. As 
it is estimated that one-fourth of the volume is taken up by egg cap- 
sules and tissue, it can be safely stated that there are at least 3,000,000 
eggs to 1 cubic centimeter. The second operation consists in remov- 
ing the ovaries from a number of scallops of a given size and meas- 
uring them in gTaduates to determine the volume of the average 
ovary. From this data the average number of eggs that a scallop 
of any size is capable of producing can be readily calculated. Twenty 
ovaries of scallops measuring 40.15 millimeters in size made 10 cubic 
centimeters, one specimen thus averaging % cubic centimeter. There- 
fore, a 40-millimeter scallop can produce about 1,500,000 eggs in a 
season. The average of seven 68-millimeter scallops made the ovaries 
of one equal to 1% cubic centimeters. Therefore, a 68-millimeter (2.7 
inches) scallop may produce in a season 4,285,700 eggs. 

At best this calculation is only an estimate. Exactness would be of 
little practical value. The errors which arise are as follows: (1) In 
computing the number of eggs to the cubic millimeter the eggs are 



OF MASSACHUSETTS. 127 

considered as spheres with intervening spaces, whereas in reality they 
are packed together in distorted shapes in the ovary. This perhaps 
offsets the second error. (2) In the second part of the computation 
the coils of the digestive tract, left in the ovary, are not allowed for, 
and with the outer covering are included in the total volume. (3) 
Another error arises from the fact that all the eggs may not be as 
large as the mature ones. (4) There is also the room taken by the 
egg capsules and tissues. "Whether these errors offset each other, or 
whether the one-fourth allowance is correct, it is impossible to state. 
However, for all practical purposes the method and count are accurate 
enough. 

Method of determining the Number of Spermatozoa produced by 
the Average Scallop in One Season. — The -method of finding the 
number of spermatozoa in the testes of a scallop is practically the 
same as in computing the number of eggs in the ovaries. It takes 260 
spermatozoa heads placed lengthwise to measure 1 millimeter, and 500 
heads placed side by side to measure the same distance. It there- 
fore takes 65,000,000 to make a A'olume of 1 cubic millimeter. By a 
generous allowance of 15,000,000,000 for tails and tissue there would 
still be left 50,000,000,000 spermatozoa to every cubic centimeter. It 
was found that the size of the testes and the ovaries in the same seal- 
lop was practically identical, and that the testes of a 40-millimeter 
and a 68-millimeter scallop measured % cubic centimeter and lYr 
cubic centimeters respectively. Thus the average 40-millimeter scallop 
is capable of producing 25,000,000,000 and the 68-millimeter scallop 
71,400,000,000 spermatozoa. 

Methods of recording Spaivning. — A variety of methods were 
employed in determining the spawning of the scallop. Chief among 
these were (a) general observation at the various scalloping localities 
of the coast; (6) microscopic examination of the eggs from the ovaries 
at different seasons; (c) the plankton net; {d) recording the color 
of the egg sac by color charts; (e) appearance of the young set in 
the different localities and at different years; (/) individual 
spawning. 

(a) General Observation. — • This method was chiefly followed in 
1905 and 1906. Trips were made to the various localities, such as 
Edgartown, Nantucket, Buzzard's Bay, Cape Cod, and the condition 
of the egg sac of a large number of scallops noted both by eye and 
by microscopical examination. The condition of the sexual products 
were then classed under three heads, (1) immature, (2) spawning, (3) 
sjDawned, according as to whether the eggs had been liberated at that 
date. By making several trips during the summer a general idea of 
the duration of the spawning season and its variation in Massachusetts 
waters was obtained. This method, though naturally inaccurate in the 
minor details, nevertheless proved extremely useful. 



128 THE SCALLOP FISHERY 

( 6 ) Microscopical Examination. — This method was used to more 
or less extent with (a), and was only of additional value in following 
the development of the immature eggs previous to the spawning season, 
showing at what period other investigations should be started. The 
eggs and sperm were removed from the ovary, placed on a slide and 
their size and appearance recorded, the sperm being classed as (1) 
active or (2) inactive. 

(c) The Plankton Net. — A small net of silk bolting cloth No. 11, 
with a diameter of 12 inches, and slightly tapering for 24 inches to 
a rounded bottom, was used for this work. By towing the net through 
the water the veliger larvse, which are abundant during spawning 
season in the water, could be captured. This is an important method 
of recording the spawning, as the presence of scallop veligers from 
two to four days old is proof that the spawning season is under way. 
By making daily towings under the same conditions and for a definite 
distance, it was possible to count the number of larvce in the water 
each day, and thus determine the conditions influencing the spawning- 
season. Although this method has been of greater value in the work 
on the other shellfish, as the same method is applicable to lamelli- 
branchs in general, a description is here given. 

The plankton net, as shown in Fig. 72, is attached in the form of 
a bag to a copper ring, to which the tow line is fastened in the same 
manner as a kite string. The outfit is trailed from the stern of a dory 
or rowboat for a definite distance at a slow, uniform rate, so that no 
outward current will sweep away the laxYse from the mouth of the 
net, which acts as a sieve to collect all microscopic organisms too large 
to pass through the meshes. 

When the proper distance is covered, the net is taken from the water 
and the contents washed into a small pail containing from 4 to 5 inches 
of clear sea water. The lamellibraneh and gasteropod larvae are now 
separated from the rest of the tow contents by giving the water a swift 
circular movement around the edge of the pail with a small stick. The 
action of the water forces the larvae to settle to the bottom at the 
center of the pail, where they can be readily transferred by a pipette 
to a watch glass for study. 

A convenient means of analyzing the towing similar to the Sedgwick- 
Rafter method of a diatom counting was devised. The larval contents 
of the towing was spread evenly throughout a cell 50 by 20 by 1 mil- 
limeters, covering an area of 1,000 square millimeters, or a cubic vol- 
ume of 1 cubic centimeter, and ten counts (M.00 of the total area), 
each covering an area of 1 square millimeter as measured with a square 
ocular micrometer, were made from different parts of the cell to get 
a representative average. The approximate number of larvae for each 
species of shellfish was obtained by multiplying the sum of these counts 
by 100. 



OF MASSACHUSETTS. 129 

(d) The Color Chart.- — ^ The color of the ovaries of a scallop is an 
excellent test of their maturity, as when distended with ripe eggs they 
generally have a rich orange hue. Before and during the spawning 
season all grades of color from a flesh pink to a deep orange can be 
found. While doubtless there is considerable variation in the color 
at maturity, the general average is sufficiently constant to warrant 
using it as a basis for recording the spawning season. By the use of 
Prang's color chart a record of the spawning of scallops in the dif- 
ferent sections was made. At Monomoy Point, by examining the color 
of the ovaries without injuring the scallop (the valves being merely 
held wide apart), the same lots of scallops were followed during the 
entire summer, and the color changes indicative of the spawning 
season charted at weekly intervals, according to the standard grades 
of color in the chart. 

(e) Appearance of Set. — By observations of the appearance of the 
set in different localities, and having already a knowledge of the age 
of the scallop at this period, the date of spawning could be correctly 
estimated. The sets, taken on the sjoat boxes at Monomoy Point, were 
carefully recorded for four years, and in other localities when oppor- 
tunity was given. 

(/) Artificial Spawning. — In order to obtain accurate data as to 
the spawning of individual scallops the following method was em- 
ployed : a large glass aquarium containing fresh sea water was placed 
on the warm sand in the sunlight. Small glass jars, each containing 
enough sea water to cover a scallop, were placed near the aquarium. 
The scallops were gently scrubbed with a brush, rinsed in a pail of 
clean salt water, and placed one in each of the small jars, under which 
dark paper was placed to facilitate detection of spawn. The usual 
number under observation at any one time was 16, which proved the 
most convenient number to watch. In order to prevent injury to the 
developing eggs by contact with metal the temperature was taken from 
a separate jar containing the same amount of water. The temperature 
of the water was taken at the time the scallops were put in and at 
the discharge of the first lot of spawn. At each spawning the contents 
of the small jar was transferred to a bottle labeled with the number 
of the scallop, number and time of discharge, and examined micro- 
scopically to determine whether eggs, spermatozoa or both were lib- 
erated. The animal and dish were rinsed in the pail, fresh water of the 
same temperature was taken from the aquarium, and the scallop re- 
turned to its former position. 

Artificial Fertilisation. - — • Two methods of artificial fertilization have 
proved most satisfactory in the study of shellfish larva: (1) removal 
of the sexual products by cutting; (2) forcing the spawning, although 
the former is not as successful with the scallop as with the oyster, 
as there are certain drawbacks, such as the crushing of the eggs, 



130 ' THE SCALLOP FISHERY 

abnoi'mal development, non-fecundation of the numerous immature eggs, 
and sacrificing the parent. The other method (forced spawning) is 
accomplished by transferring the scallops from cool to warmer water, 
which causes the ripe egg-s to be extruded in a more natural manner. 
Spawn could be obtained at any time during the season if the tem- 
perature was satisfactory, and the same scallops could be used over 
and over. 

In raising the larv« for laboratory study the aquaria should be 
kept clean, a relatively large amount of water for a few larvae should 
be allowed, as crowding results in death, and the decomposing eggs, 
if not separated by siphoning off the surrounding embryos, soon cause 
the death of all. With every precaution the death rate is very high, 
owing to the debris, parasitic protozoa, bacteria, etc., which collect 
in the water, but there is good reason to believe that "by careful experi- 
ment scallops can be raised in numbers in the laboratory, although 
during this investigation only a few were successfully carried to the 
post-embryonie stage. 

Artificial Propagation. — The object of artificial propagation is 
the prevention of the great " infant mortality," as under natural con- 
ditions but %o,ooo of 1 per cent, of the number of eggs develop into 
mature scallops. Artificial fertilization and the protection of the 
young embryos during the first few days of life would to a large extent 
do away with this gTeat loss; but the practical difficulties in success- 
fully rearing the larvse over this period are such as to make the under- 
taking problematic. At the present time liberation of the eggs imme- 
diately after artificial fertilization seems to be of most benefit to the 
fishery. 

The Rate of Growth. 
Methods of measuring the Scallops. — Three measurements were 
made of each scallop (Fig. 65) : (1) height, along the dorso-ventral 
axis, or from the hinge to the opposite edge of the shell; (2) width, 
along the antero-posterior axis, or from the left to right edge of the 
shell; (3) thickness, along the lateral axis, or the depth through the 
valves. 

The growth of any mollusk can only be accurately stated by deter- 
mining the gain in volume. As it was obviously impossible to obtain 
the water displacement of the scallop with its loose shell, the following- 
method of calevdating the volume was devised : the three dimensions 
of the scallop were multiplied together and the result called the cubic 
volume, equivalent to the volume of a solid rectangular prism of 
those dimensions, in which the scallop is theoretically enclosed. Thus 
the following proportion can be established : scallop A of cubic vol- 
ume 1,000 is to scallop B of cubic volume 5,000 as 1,000 is to 5,000 
(A :B:: 1,000:5,000). Thus scallop B is five tunes, or 500 per cent., 
larger than scallop A, and the relative per cent, of increase is ob- 



OF MASSACHUSETTS. 131 

tained with the same results as if the water displacement had been 
taken. By taking several hundred measurements of width and thick- 
ness for scallops of the same height a table has been formulated, 
giving the average width, thickness and cubic volume for every sized 
scallop. Thus having given the height of any scallop, the cubic vol- 
ume can be found and any gain in length transformed into gain in 
volume. 

Measuring Instrument. — For speed, exactness and uniformity in 
measuring large numbers of scallops it was necessary to have a suitable 
measuring implement. (Fig. 105.) The instrument, designed for this 
work by the writer, consists of an inverted triangle, formed by two 
strips of metal welded together at the apex of the triangle, and joined at 
the base by a short cross piece. The whole instrument is made of brass 
except the braised joint, and can be made as light as desired, although 
there is danger of a heavy blow rendering a light measurer inac- 
curate. Several sizes were used in the work, the most convenient 
having a base measuring 3 inches. On the sides of the triangle the 
scale is marked in millimeters. The measure is sealed in a simple 
manner by taking across the broad end a certain width in millimeters, 
measuring the length of the instrument, and subdividing it into a cer- 
tain number of equal parts, each corresponding to 1 millimeter. 
This gives easier and more accurate readings as it is possible to read 
to % of a millimeter with the same accuracy as to 1 milHmeter on an 
ordinary rule, each division on the triangle having actual measurement 
of nearly 5 millimeters. When measuring, the triangle is held with the 
base away from the body, and the object is brought doY>?n the nar- 
rowing sides until it strikes, at which point the measurement is read. 

The value of the instrument arises from the rapidity with which 
measurements can be made, as only one movement is required to record 
'the length of an object. Measurements could be made nearly twice 
as fast as by using calipers, where two movements are required. A 
proficient person can measure as high as 400 scallops per hour, three 
measurements being taken for each scallop, or a total of 1,200. The 
ordinary person can measure about 300 in the same time, or 5 scallops 
per minute. This instrument can be used for measuring a variety of 
objects, and students of variation, where rough measurements are alone 
required, will find it of great convenience. 

Growth Experiments. — The growth experiments were carried on in 
two ways: (1) by measurements at definite periods of the various sets 
in the different waters of the Commonwealth; (2) by growth in pens 
at Monomoy Point, Monument Beach, Marion and Chatham. 

In the first case the work chiefly consisted of measurements, taken 
as described above, of a large number of scallops at each time, so as 
to obtain a correct average. During the first year three measurements 
of each scallop were made, until sufficient material was at hand to 



132 THE SCALLOP FISHERY 

formulate Table D. Afterwards only one measurement, the height, 
was taken, as the gain in volume for any locality could be determined 
from the table. The growth line proved of great assistance, as the 
increase from May 1 at any date could be determined by making two 
measurements, (1) the height, and (2) the growth line. 

Tagged Scallops. — A method of recording the growth of individual 
scallops as well as obtaining data upon their migratory habits was 
obtained by " tagging " each specimen. A small hole was punched 
through the " ear " close to the hinge line, and a numbered copper 
tag was attached by a fine wire, as in Fig. 66. The scallops were 
then liberated in the Powder Hole, after their measurements were taken. 
Whenever found, the number and size were recorded, thus obtaining 
the exact growth of the individual specimens. The tag apparently did 
not interfere with the growth or movements of the animals. 

Another method of identification was used in the pens. The scallops 
were notched with a file across one valve, the number of notches giving 
the class of the scallop when more than one size were confined in the 
pen. 

The Pens. — Most of the growth experiments were conducted in 
pens (Fig. 80)', as the activity of the scallop rendered confinement 
necessary. In this way, under what might be termed artificial con- 
ditions, the rate of growth of Pecten irradians was obtained in several 
localities. The pens were of two kinds: (1) of 1%,-inch wire chicken 
netting; (2) of old seines. They were constructed by driving in the 
soil posts of 2 by 3 inch joist, at sufficient intervals to hold the netting 
firmly in position. When wire netting was used little difficulty was 
experienced in making the bottoms of the pens tight to prevent the 
escape of the scallops, as the netting set firmly on the soil, which had 
previously been leveled. When seines were used the bottom was se- 
cured either by baseboards or by fastening the netting by long wooden 
pegs, an uncertain method at best. The pens were made either of a 
sufiicient height to rise above the average tide, which was possible 
at Chatham and Monomoy Point, where there is a comparatively small 
rise and fall of the tide, or were fitted with netting tops when the tide 
proved high, as at Marion and Monument Beach. The pens, which 
ranged from 40 to 400 square feet in size, were situated in water from 
1 to 21/^ feet in depth at low tide, and iinder a variety of conditions 
as regards current, soil, eel grass and tide. 

Wire Cages. — Scallops were suspended in wire cages (Fig. 71) from 
a raft in the Powder Hole, Monomoy Point, in order to obtain the rate 
of growth, especially of the young " seed," too small to confine in pens. 
The baskets consisted of a wooden framework, 2^/2 feet long, 1^/2 feet 
wide, 1 foot deep, covered by netting with %, to 1^ inch mesh. 
Smaller cages were used for the young scallop with galvanized mos- 
quito netting. The objection to the use of a small mesh is due to the 



OF MASSACHUSETTS. 



133 



restriction of the water circulation by the clogging of the fine meshes 
by plant growth. This was avoided as much as possible in the growth 
experiments by frequently cleaning the cages, and transferring the 
small scallops as soon as their size permitted to the larger cages. In 
spite of this care the growth of the " seed " inside the cages proved 
less than those attached outside. Old scallops, as well as young, were 
confined in the baskets for growth records. 

The Biological Raft. — The raft (Fig. 79) from which the wire 
baskets were suspended proved particularly useful in the study of the 
post-embryonic life history of the scallop, which " set " in numbers 
on the boxes, wire cages and ropes, where specimens could be obtained 
in all stages of development for laboratory examination. From the 
raft at various depths were suspended wire cages and boxes, in which 
growth experiments upon the quahaug, clam and scallop were con- 
ducted. The raft, 20 feet long by 10 feet wide, was made of two 4 
by 6 inch beams, 20 feet long, which were held in place by cross beams, 
3 by 4 inches in size. On the framework was a floor, except for a 
large central " well." Four trapdoors led to smaller " wells " on each 
side. The raft was buoj^ed by six oil barrels, two on each end and 
two on the sides, and was moored in the Powder Hole in 20 feet of 
water. The scheme of box spat collecting from a raft is recommended 
to biological students, as the young of many worms, crustaceans, mol- 
lusks and other marine forms are caught easily in sand boxes. 





A 


. Life Table. 




Stage. 


Age. 


Shape. 


Size (Inches) . 


Movement. 


Egg, . . . 


- 


Spherical, 


Hoc, • . 


None. 


Two cells, . 


46 minutes. 


- 


%ob, 


None. 


Four cells, . 


67 minutes. 


- 


Vioo, 


None. 


Eight cells, . 


81 minutes, 


- 


Vioo, . 


None. 


Sixteen cells, 


100 minutes. 


- 


V400, • 


None. 


Blastula, 


9 hours, . 


Mulberry, 


ViOQ, 


None. 


Ciliated gastrula, 


10 hours, . 


- 


%00, 


Cilia. 


Trochosphere, 


12 hours, . 


Elongate, 


%00, 


Cilia and flagellum. 


Early veliger, 


40 hours, . 


Flat hinge, . 


V-215, ■ 


Velum. 


Late veliger, 


5 days, . 


Umbones, 


Wo2, • 


Foot. 


Dissoconch, . 


8 days, . 


Scallop, . 


yi52 to Vao, . 


Foot. 


Plicated, 


20 days, . 


Scallop, . 


V20 to ys. 


Foot and valves. 


Youth, . 


Up to 1 year, . 


Scallop, . 


Vs to is/s. 


Valves. 


Adult, . 


Over 1 year, 


Scallop, . 


is/s to IV2, ■ 


Valves. 



134 



THE SCALLOP FISHERY 





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•lilt 




1 








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1 1 1 1 1 1 1 1 1 1 1 1 


1 






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'5 

t 
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] 3 ^ 


Heart and blood system, . . . . 
Reproductive organs, 



OF MASSACHUSETTS. 135 



G. Stages of Development. 
In order to give a brief consecutive narrative to the life history 
of the scallop it was found necessary to confine the detailed descrip- 
tions of the period following the time of " set " to the reference 
portion of the report. For this purpose the life of the young scallop 
during the dissoconch and the plicated stages has been arbitrarily 
divided into eight periods. The chief characteristics of each of these 
periods are described in tabulated form and refer to the drawings 
of the early stages. In making the divisions the shell has been taken 
as the standard, and each stage is differentiated by some change in 
formation. 



136 



THE SCALLOP FISHERY 



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OF MASSACHUSETTS. 



137 



D. Comparative Table of Size and Volume. 
In the following table of scallops from 1 to 80 millimeters for each 
size (height), the average width and thickness are taken from the 
measurements of many specimens. Height is the measurement along 
the dorso-ventral axis, or from the hinge to the opposite edge of the 
shell; width, along antero-posterior axis, or from the left to right 
edge of the shell; thickness, along the lateral axis, or the depth through 
the valves. The cubic volume is expressed in cubic millimeters as 
height times width times thickness. For each size the number per 
quart is given in the fifth column. This table proved very useful in 
determining the gain in volume in the planted beds and in the localities 
under observation, as by merely having the original size and increase 
in height, the gain in volume could be readily calculated. 



i 

PI 




1 


6 

a 

"o 


1 

%l 

'A 


1 




1 


6 

a 




1 


1.0 


.2 


.2 


7,927,275.00 


25 


25.0 


8.9 


5,563.0 


285.00 


2 


1.8 


.5 


1.8 


880,820.00 


26 


26.0 


9.3 


6,287.0 


252.20 


3 


2.7 


.8 


6.5 


243,960.00 


27 


27.0 


9.7 


7,071.0 


224.20 


4 


2.6 


1.1 


11.4 


138,596.00 


28 


28.1 


10.1 


7,947.0 


199.50 


5 


4.5 


1.5 


33.8 


45,898.00 


29 


29.2 


10.5 


8,891.0 


178.30 


6 


5.4 


1.8 


58.3 


27,195.00 


30 


30.3 


11.0 


9,999.0 


158.30 


7 


6.3 


2.1 


92.6 


17,123.00 


31 


31.4 


11.5 


11,194.0 


141.60 


8 


7.3 


2.5 


146.0 


10,859.00 


32 


32.5 


11.9 


12,376.0 


128.10 


9 


8.3 


2.8 


209.0 


7,583.00 


33 


33.6 


12.4 


13,749.0 


115.30 


10 


9.3 


3.1 


2S8.0 


.5,506.00 


34 


34.7 


12.9 


15,219.0 


104.20 


11 


10.2 


3.4 


382.0 


4,150.00 


35 


35.8 


13.3 


16,665.0 


95.00 


12 


11.2 


3.8 


511.0 


3,103.00 


36 


36.9 


13.7 


18,199.0 


87.10 


13 


12.2 


4.1 


650.0 


2,439.00 


37 


38.0 


14.1 


19,825.0 


80.00 


14 


13.2 


4.4 


813.0 


1,950.00 


38 


39.2 


14.5 


21,599.0 


73.40 


15 


14.2 


4.8 


1,022.0 


1,551.00 


39 


40.4 


15.0 


23,634.0 


67.10 


16 


15.3 


5.2 


1,273.0 


1,245.00 


40 


41.6 


15.5 


25,792.0 


61.40 


17 


16.4 


5.6 


1,561.0 


1,016.00 


41 


42.8 


16.0 


28,077.0 


.56.50 


18 


17.5 


6.0 


1,890.0 


838.80 


42 


43.9 


16.5 


30,423.0 


52.10 


19 


18.6 


6.4 


2,262.0 


700.90 


43 


45.0 


17.0 


32,895.0 


48.20 


20 


19.6 


6.8 


2,666.0 


595.60 


44 


46.2 


17.5 


3.5,574.0 


44.60 


21 


20.7 


7.2 


3,130.0 


506.40 


45 


47.4 


18.0 


38,394.0 


41.30 


22 


21.8 


7.6 


3,645.0 


434.90 


46 


48.6 


18.5 


41,359.0 


38.50 


23 


22.9 


8.0 


4,214.0 


376.20 


47 


49.8 


19.0 


44,471.0 


35.65 


24 


23.9 


8.5 


4,876.0 


325.20 


48 


50.9 


19.5 


47,642.0 


33.30 



138 



THE SCALLOP FISHERY 



'3 
W 




1 
i3 

H 


6 
o 
1 


i 

.o u 

as. 
12; 


.i 


;g 


o 

a 

i 


6 

o 

o 


+3 

f-t 

1? 

iz; 


49 


52.1 


20.0 


51,058.0 


31.00 


65 


70.3 


29.6 


135,257.0 


11.72 


50 


53.2 


20.5 


54,530.0 


29.10 


66 


71.4 


30.2 


142,314.0 


11.14 


51 


54.4 


21.1 


58,540.0 


27.20 


67 


72.6 


30.8 


149,817.0 


10.58 


52 


55.5 


21.7 


62,626.0 


25.30 


68 


73.8 


31.5 


158,080.0 


10.03 


53 


56.7 


22.3 


67,014.0 


23.65 


69 


75.0 


32.2 


166,635.0 


9.51 


54 


57.9 


22.9 


71,599.0 


22.15 


70 


76.2 


32.9 


175,489.0 


9.03 


55 


59.1 


23.5 


76,387.0 


20.75 


71 


77.4 


33.7 


185,195.0 


8.56 


56 


60.3 


24.1 


81,381.0 


19.50 


72 


78.6 


34.5 


195,242.0 


8.12 


57 


61.4 


24.7 


86,445.0 


18.34 


73 


79.8 


35.2 


205,054.0 


7.73 


58 


62.5 


25.3 


91,713.0 


17.30 


74 


81.0 


35.9 


215,184.0 


7.37 


59 


63.6 


25.9 


97,187.0 


16.30 


75 


82.1 


36.6 


225,364.0 


7.03 


60 


64.7 


26.5 


102,873.0 


15.40 


76 


83.2 


37.3 


233,855.0 


6.72 


61 


65.8 


27.1 


108,774.0 


14.58 


77 


84.4 


38.1 


247,604.0 


6.40 


62 


67.0 


27.7 


.115,066.0 


13.78 


78 


85.6 


38.9 


259,728.0 


6.14 


63 


68.1 


28.3 


121,415.0 


13.06 


79 


86.8 


39.7 


272,231.0 


5.82 


64 


69.2 


29.0 


128,435.0 


12.34 


80 


88.0 


40.3 


285,120.0 


5.56 



BIBLIOGRAPHY. 

1. Drew, G. A. The Habits, Anatomy and Embryology of the Giant 

Scallop (Pecten tenuicostatus Mighels). The University of Maine 
Studies No. 6, 1906. 

2. Eisser, Jonathan. Habits and Life History of the Scallop (Pecten 

irradians). Thirty-first Annual Report of the Commissioners of In- 
land Fisheries of the State of Ehode Island, 1901. 

3. Kellogg, J. L. Feeding Habits and Growth of Venus mercenaria. New 

York State Museum Bulletin No. 71, Zoology 10, 1903. 

4. Jackson, E. T. Phylogeny of the Pelecypoda. Memoirs Boston Society 

Natural History, Vol. IV, 18. 

5. Kellogg, J. L. The Clam and Scallop Industries. New York State 

Museum Bulletin No. 43, Vol. 8, 1901. 

6. Kellogg, J. L. A Contribution to our Knowledge of the Morphology of 

Lamellibranchiate MoUusks. Bulletin United States Fish Commission, 
1890. 

7. Kellogg, J. L. Notes on the Marine Food Mollusks of Louisiana. Gulf 

Biological Station Bulletin No. 3, 1905. " 

8. Ingersoll, E. The Scallop Fishery. In the Fisheries and Fishing In- 

dustries of the United States, United States Fish Commission and 
Tenth Census, 1887. 

9. Pelseneer, P. A Treatise on Zoology. Part V., Mollusca. Edited by 

E. Eay Lankester, London, 1906. 
10. Kellogg, J. L. Shell-fish Industries, 1910. Henry Holt & Co. 



OF MASSACHUSETTS. 



139 



11. Clark, A. H. The Fisheries of Massachusetts. In the Fisheries and 

Fishing Industries of the United States, United States Fish Commis- 
sion and Tenth Census, 1887. 

12. Smith, H. M. The Giant Scallop Fishery of Maine. United States 

Fish Commission Bulletin for 1889, Vol. 9. 

13. Howell, W. H. A Text-book of Physiology, 1909. 

14. Langworthy, C. F. United States Department of Agriculture, Farmers' 

Bulletin 85, 1898. 

15. Sharp, B. Eemarks on the Phylogeny of the Lamellibranchiata, Proc. 

Acad. Nat. Sc, Phila., 1888. 



Adductor muscle, 

Anterior, 

Archenteron, 

Asymmetrical, 

Auricle, 

Bathymetrical, 

Blastopore, . 

Blastula, 

Byssus, 

Cell, . 
Cilia, . 
Cleavage, 
Cloacal chamber. 

Crystalline style, 

Cytoplasm, . 
Diatoms, 

Dimyarian, . 
Dissoconch, 

Dorsal, 

Ectoderm, . 
Egg, . 
Egg capsule, 
Embryo, 
Endoderm, . 
Equilateral, 
Bquivalvular, 
Exoskeleton, 



GLOSSARY. 

Muscle which draws the two valves (shells) to- 
gether. 

Front. 

Primitive or original digestive tract. 

Not symmetrical. 

A chamber of the heart. 

Eelating to the depth in the sea. 

The opening into the archenteron. 

An early stage in the development of the embryo, 
in which the outer cells form a definite layer. 

Thread-like fibers secreted by the foot for attach- 
ment. 

The unit structure of life. 

Filamentous protoplasmic processes. 

Natural division of the egg cells. 

Space into which waste material is discharged be- 
fore passing out the excurrent siphon. 

A transparent gelatinous rod which lies along the 
upper part of the intestine. 

That part of the protoplasm outside of the nucleus. 

Microscopic plants, which constitute the food of 
the shellfish. 

Having two adductor muscles, as the quahaug. 

Literally, two shelled; babyhood shell with no pli- 
cations. 

Eeferring to the back of the animal but not neces- 
sarily the upper side. 

The external outer layer of cells. 

The female germ cell — ovum. 

Case in which the egg is inclosed. 

The first rudiments of an organism. 

The inner cell layer. 

Having all sides equal. 

"When two valves are alike in size and shape. 

Outside framework or support, differing from a 
true skeleton or endoskeleton, which is inside 
the body. 



140 



THE SCALLOP FISHERY 



Fecundation, 
Fertilization, 
Flagellum, . 
Follicle, 
Formative cells, . 

Ganglion, 

Gastrula, 

Genus, 
Geotropic, . 
Germ cell, . 
Gills, . 

Gland, 

Hermaphrodite, 

Invagination, 

Lamella, 
Lamellibranchiata, 

Larva, 

Lumen, 
Macromere,- 

Micromere, . 

Mantle, 

Mantle cavity. 
Maturation, 

Migration, . 
Monomyarian, 

Nacreous structure. 
Nucleoli, 
Nucleus, 
Otocysts, 



Ovum, 
Pecten, 
Pericardium, 
Posterior, . 



Impregnation of the ovum by the spermatozoon. 

Fecundation. 

A long, whip-like cilium. 

A small cavity. 

Cells which form the animal in contrast with cells 

which furnish them with food. 
A mass of grey nervous substance, which serves 

as a center of nervous influence. 
An embryonic stage which has the form of a 

double-walled sac with an opening leading into 

a cavity, the archenteron. 
Group of species. 

Showing a disposition to incline toward the earth. 
That which is to develop a new individual. 
Eespiratory organs in water, comparable to the 

lungs in air. 
A cell or collection of cells having the power of 

secreting. 
An animal having both male and female generative 

organs. 
One of the methods by which the various germinal 

layers of the ovum are differentiated. 
A thin plate or scale. 
Animals of the mollusk family that have the gills 

arranged in leaf -like layers. 
The animal during its development until it reaches 

adult size. 
An opening, space or cavity. 

One of the larger cells, resulting from segmen- 
tation of the egg. 
One of the smaller cells, resulting from segmen- 
tation of the egg. 
The fleshy, membraneous covering, lining inside of 

the shell. 
The space between the mantles. 
The process of ripening or coming to maturity of 

the egg. 
Act of traveling from one region to another. 
Having one adductor muscle, as with the scallop 

and oyster. 
Pearly layer of shell, generally on the inside. 
Smaller divisions or parts of the nucleus. 
Germinative spot. 
Organs of equilibration. 
The organ of a female in which the eggs are 

formed. 
The egg. 

Scientific name of the scallop. 
Membrane inclosing the heart. 
Opposite to anterior. 



OF MASSACHUSETTS. 



141 



Prismatic structure, 

Prodissoconch, 

Protandrie, 

Protoplasm, 
" Seed " scallop. 
Set, . 
Spawning, . 
Spermatozoon, 
Tentacle, 

Testis, 
Trochosphere, 

Umbo, 
Valves, 

Veliger, 

Velum, 



Ventral surface, 
Ventricle, . 
Visceral mass. 



Shell made up of prisms. 

Small embryonic shell of a moUusk. 

Having male sexual organs while young, and female 

organs later in life. 
Cell contents — life substance. 
A scallop less than one year old. 
Attaching of scallop by byssus. 
To set free the eggs or spermatozoa. 
The male sex cell. 
A more or less elongated process, usually an organ 

of sense or motion. 
The male gland which produces the spermatozoa. 
Stage in embryonic development, in which the em- 
bryo is spherical and rotates rapidly. 
The beak or " shoulder " of the bivalve shell. 
Two valves, the right and left, compose the shell 

of a lamellibranch mollusk. 
Stage in embryonic development in which velum is 

used as an organ of locomotion. 
A circular pad covered with cilia and used as an 

organ of locomotion in the early embryonic 

stages. 
The side opposite the dorsal surface. 
A chamber of the heart. 
That part of body containing digestive, generative 

and part of circulatory and nervous systems. 



INDEX. 



INDEX 



Acmsea, 

Adductor muscle, 

Age, 

Anatomical development, 

Anatomy of adult, . 

Anatomy of dissoconch stage, 

Anatomy of veliger, 

Anomia, . 

Assistants, 

Attachment, 

Observations on 

Period of, . 

Value of, . 
Bait regulation, 
Barnstable, 
Bibliography, . 
Blastula, 
Bourne, . 
Brewster, 
Buzzard's Bay, 
Byssal groove, 
Byssus, . 
Cage growth, . 
Cages, wire, 
Cape Cod: — 

Spawning season, 

Growth, . 
Catch, daily limit to, 
Champi parvia, 
Chatham, 
Chatham dredge. 
Ciliated larva, . 
Circulatory system, 
Cleavage, 
Climbing, 
Color: — 

Chart, 

Preference, 

Variation, 
Courtesies, 
Crawling, 
Crepidula, 
Culture : — 

7\jtificial, . 

Communal, 



73, 83 



PAGE 

14, 71 
16, 46 
. 77-81, 87 
41-47 
13-19 
38, 39 
32-35 
14, 71 

11 
50-54 

53 

52, 53 

53, 54 
119 

98, 100, 101, 104 
. 138, 139 

29 
. 102, 104 

98 
85, 101, 102 

38 
. 18, 51, 52 
. 89, 90, 96 
. 132, 133 

25 

85 

118 

14 

85, 99, 100, 104 

109 

29, 30 

17 

28, 29 

56, 57 

129 

67 

48 

10, 11 

54-56 

14, 71 

. 122, 123 
. 123, 124 



146 



INDEX. 



Current, . 

Death of old scallops, 

Decline of industry. 

Deformities, 

Dennis, . 

Development table, 

Diatoms, 

Digestive system : — 

Anatomy, 

Development, 

Veliger, 
Dissoconch stage, 
Distribution, . 
Dredges, 
Dredging, 
Drew, Prof. G. A., 
Drifting, 
Edgartown, 
Eel grass, 
Egg: — 

Description, 

Development, 

Method of counting, 
Embryological methods, 
Embryology, . 
Enemies, 
Enteromorpha, 
Environment, . 
Excretory system, 
"Eye," . 
Eyes: — 

Anatomy, 

Development, . 
Fairhaven, 
Fallacies, 
Falmouth, 
Family, . 
Fecundation : — 

Natural, . 

Self, 
Feeding habits. 
Fertilization : — 

Artificial, . 

Self, 

Two-year-old scallops 
Fishery, . 

Methods of improving 
Fishing grounds, 
Flagellutn, 
Food value, 
Foot: — 

Anatomy, 

Development, 
Footed larva, . 
Gastrula, 



10, 



88-90 

79 

106, 107 

95 

100, 104 
135, 136 

65 

17 

46,47 

35 

36-39 

12 

109, 110 

108-110 

11, 13, 18, 27, 58 

60, 61 

83, 85, 103, 104 

. 88, 89, 91 

19 

27, 28 

. 126, 127 

. 125-130 

27-31 

67-73 

13 

87-92 

17, 18 

111, 116, 117 

15, 16 
44 

101, 104 
73 

102 
11, 12 

25,26 

26 

65,66 

129, 130 
26 

26,27 

107-112 

124, 125 

97-103 

30 

113-117 

18 
46 
34 
29 



INDEX. 



147 



Gates, W. H., . 
Gathering by hand, 
Gills: — 

Anatomy, 

Development, 

Feeding, . 
Glossary, 
Growth: — 

Artificial, . 

Average, . 

Buzzard's Bay, 

Cage, 

Cape Cod, 

Chatham, 

Conditions influencing, 

Current, . 

Eel grass. 

Environment, 

Food and, 

General, . 

Line, 

Locality, . 

Methods, . 

Months, . 

Natural compared with artificial, 

Pen, 

Salinity, . 

Sets of 1904, 1905, 1906, 

Shellfish, . 

Size and, . 

Soil, 

Spawning season, 

Temperature, 

Variations, 

Water, depth of, 

Young scallops, 
Harwich, 
Heart, 
Hinge, 
Hinge line. 
History of fishery, 
Industry, statistics of, 
Ingersoll, Ernest, 
Intestine, 
Islands, . 

Jackson, Prof. R. T. 
Kellogg, Prof. J. L., 
Kidney, . 
Laws, 

Life, length of, 
Light, effect of. 
Liver, 

Locomotion, 
Macromeres, . 
Man, 



10 



13, 18, 32, 



8, 11 
107, 108 

16 

45,46 

66 

139-141 

92-96 

74. 84, 85 

85 

89, 90, 96 

85 

99, 100 

87-92 

88-90 

91 

87 

75 

75 

14, 81, 82 

85 

74, 75, 130-133 

76,77 

93, 94 

94, 96, 97 

92 

85 

76 

95 

91 

82,83 

91 

76 

92 

83,84 

100, 104 

17 

14 

13 

105, 106 

103, 104 

10, 12, 72, 77, 123 

17,47 

85 

36, 37, 51, 52, 58, 59, 64, 66 
10-12, 17-19, 66 
17, 18 
117-120 
77-81 
66 
17,47 
54-60 
29 
71-73 



148 



INDEX. 



Mantle : — 

Anatomy, 

Development 

Veliger, 
Marion, . 
Market, . 
Mashpee, 
Mattapoisett, . 
Measuring instrument, 
Methods: — 

Fishing, 

Improving industry, 

Investigation, 
Micromeres, 
Migration, 
Monomoy, 
Muscle, adductor, 
Names, . 
Nantucket, 
Nassa obsoleta. 
Natural supply. 
Nervous system. 
Net, plankton, 
New Bedford, . 
Non-edible parts, 
North Falmouth, 
Object of report, 
Openers, 

Opening, method of, 
Orleans, . 
Otocyst, . 
Outfit of scalloper. 
Ovary, 
Overcrowding and growth 
Oyster drill. 
Palps, 
Pelseneer, Dr. Paul, 
Penalties for scallop laws, 
Pens, 

Permits for fishing, 
Plicated stage. 
Polar cells. 
Powder Hole, . 
Power, scalloping by. 
Presentation of report. 
Price, market, 
Prodissoconch 
Propagation, 
Provincetown, 
Pusher, . 
Raft, biological 
Range, 
Readers, 

Recovery from injury, 
Reproductive organs. 
Resting, . 



20, 21, 



15 

41,42 

35 

83, 85, 102, 104 
111, 112 
101 
101, 104 
131 



107-110 

121-125 

1, 125-133 

29 

61-64 

, 85, 86, 89 

16, 34, 46 

12 

85, 102, 104 

70,71 

121-124 

17 

128 

101, 104 

116 

83,85 

9 

111 

111, 112 



23,83 



94, 



45 

110 

18 

96 

69,70 

16, 17, 46 

20, 26, 30 

119 

96, 97, 132 

119, 120 

39,40 

28 

11,79 

110,111 

9, 10 

112 

32 

122, 130 

99 

108 

11, 133 

12, 13 

8 

64, 65 

18,19 

60,61 



INDEX. 



149 



Restocking, 
Rhode Island, 
Ridges, . 
Risser, Jonathan, 
Salinity, . 
Savery, Charles L., 
Sea weeds, 
Season, . 
Seed scallop, 
Senility, . 
Sense organs, . 
Sensory powers, 
Serpula, . 
Set, 

Shanties, 
Shell, 
Shipment, 
Soaking, 
Soil, 

Spat collecting. 
Spawning, 
Age, 

Artificial, . 
Growth, . 
Methods of recording 
Monomoy Point, 
Season, 
Temperature, 
Spermatozoa, . 
Stage harbor, . 
Stages : — 

Dissoconch, 
Life, 

Plicated, . 
Veliger, 
Starfish, . 
Stomach, 
Swimming, 
Tables, . 

Dissoconch phases, 
Life, 

Volume, . 
Tagged scallops, 
Temperature : — 
Spawning, 
Growth, 
Tentacles, 
Terminology, 
Testis, . 
Tisbury, . 
Traveling, rate of, 
Trochosphere larva. 
Turning over, . 
Two-year-old scallopi 
Ulva, 
Valves, . 



13 



36, 
15,31 



10,77 



50,51 

,47- 



49 



PAGE 

124 

86 

13,14 

82, 83, 86 

92 

8, 11 

14 

107, 118 

119 

78,79 

42-45 

66,67 

14,71 

, 83, 85, 86 

111 

116, 117 

112 

114, 115 

91 

54 

20-25 

22 

129 

82, 83 

127-129 

20,21,23 

23-25 

22 

19, 20, 127 

90 

36-39 

78 

39,40 

31-35 

68,69 

16,47 

30, 57-60 

133-138 

135, 136 

133, 134 

137, 138 

63, 132 

22 

91,92 

15, 42-44 

9 

18 

104 

57 

30 

57 

79 

14 

13 



150 



INDEX. 



I 



Variation : — 

Color, 

Growth, . 

Length of life, 
Veliger, . 
Vehim, . 
Vinal, William G., 
Vineyard Haven, 
Visceral mass, 
Vision, 
Wareham, 
Wellfleet, 
Yarmouth, 
Yolk lobe. 



48,49 

95 

80 

31-35 

33 

8, 11 

103, 104 

46 

67 

102, 104 

99 

73, 100, 104 
28 



ABBREVIATIONS. 



a. — anus. 


7)if. — mantle flap. 


aa. — anterior adductor muscle. 


mt. — mouth. 


b. — byssus. 


0. ■ — otocyst. 


bg. — byssal gland. 


og. — outer gills- 


bgr. — byssal groove. 


ov. — ovary. 


bn. — byssal notch. 


pa. — posterior adductor muscle 


d. — dissoconch. 


pc. — polar cells. 


di. — distal end. 


pd. — prodissoconch. 


er. — " ear." 


pi. ■ — plicated growth. 


/. — foot. 


pm. — primitive mouth. 


fc. — foot cleft. 


pr. — proximal end. 


fg. — foot groove. 


ps. — pseudo-siphon. 


fl. — flagellum. 


r. — retractors of velum. 


fr. — foot retractor muscle. 


s. — stomach. 


g, — • gills. 


sg. — shell gland. 


h. — hinge line. 


t. — tentacles. 


ht. — heart. 


te. — teeth. 


i. — intestine. 


ts. — testis. 


ig. — inner gills. 


V. — velum. 


I. — liver. 


vm. — visceral mass. 


Ip. — labial palps. 


yl. — yolk lobe. 


m. — mantle. 





Pig. 1. — Mature egg ready for union with male cell. Magnified 600 diameters. 

Fig. 2. — Spermatozoa (male ceils). Note length of tail and variation in shape 
of head. The spermatozoon on the left is the most common form. No attempts 
were made to study the minute anatomy. Magnified 600 diameters. 

Fig. 3. — - Compressed egg. Shape due to pressure of eggs within ovary. 
Shortly after extrusion it becomes spherical. Magnified 600 diameters. 

Fig. 4. — Egg enclosed in membranous case. Magnified 600 diameters. 

Fig. 5. — ■ Egg, forty-three minutes after fecundation, showing the yolk lobe 
(yl) and two polar cells (pc). The formation of the yolk lobe has given to the egg 
a pear-shaped appearance. Magnified 600 diameters. 

Pig. 6. — Ring of spermatozoa with radiating tails held away from the egg by 
a membrane. The entire surface of the membrane is covered by the sperma- 
tozoa, but only those in one plane are here shown. Magnified 600 diameters. 

Fig. 7. — Two-celled stage, forty-six minutes after fecimdation, showing unequal 
division. The larger cell contains the yolk lobe (yl) . Magnified 600 diameters. 

Pig. 8. — ■ Four-celled stage, sixty-seven minutes after fecundation. Magni- 
fied 600 diameters. 



Fig. 9. — Eight-celled stage, side view, eighty-one minutes after fecundation. 
Magnified 600 diameters. 

Fig. 10. — Sixteen-celled stage, viewed from below, one hundred minutes after 
fecundation. Note large yolk cell. Magnified 600 diameters. 

Fig. 11. — ■ Blastula stage, viewed from below, about nine hours after fecunda- 
tion. The original egg has developed, by repeated divisions, into a mass of cells, 
giving it a mulberry-like appearance. The large yolk cell has divided into four 
macromeres, the rest of the cells constituting the micromeres. Magnified 600 
diameters. 

Fig. 12. — Ciliated gastrula, ten hours after fecundation. The embryo can now 
swim through the water by means of the hair-like cilia. The larger cells have 
become invaginated. Magnified 600 diameters. 

Fig. 13. — Optical section of ciliated gastrula. Magnified 600 diameters. 

Fig. 14. — Trochosphere stage, twelve to fourteen hours after fecundation. 
The body has elongated and the cilia are now confined to the front end. Note 
the long feeler or fiagellum, which serves to guide the animal. The opening of the 
primitive mouth can be seen on the lower side, while above is a slight indentation 
corresponding to the beginning of the shell gland. Magnified 600 diameters. 

Fig. 15. — Formation of the shell, which arises at two symmetrical points of 
calcification, right and left of the median line, and gradually envelops the animal. 
Magnified 600 diameters. 

Fig. 16. — Early veliger larva, viewed from the side. The animal arrives at 
this stage from seventeen to forty hours after fertilization, according to external 
conditions. The duration of this stage is probably from five to six days, during 
which the animal leads a free swimming life. Magnified 600 diameters. 







MW,r 










10 



13 







% 



%.Vl//ll.!f 



^"§1 



16 



Fig. 17. — Early veliger swimming with velum extended. Viewed from side. 
Magnified 150 diameters. 

Fig. 18. — Late veliger or prodissoconch. Note change in form of shell, as 
compared with Fig. 17. This stage marks the end of the embryonic period, as the 
scallop now forsakes its free swimming life and attaches itself to objects by means 
of its byssus or "anchor strands." Magnified 150 diameters. 

Figs. 19 to 32, inclusive, cover the next distinct stage of development. This 
form is called "dissoconch," i.e., double shell. 

Fig. 19. — Dissoconch Phase 1. Early dissoconch growth after scallop has "set." 
View of right or lower valve. Note beginning of byssal or foot notch (bn). Scal- 
lop is now capable of byssal attachment. Right valve is slightly smaller than left. 
Magnified 150 diameters. 

Fig. 20. — View of left valve of same scallop as in Fig. 19. Anatomy shown 
through transparent shell. Note increased number of gUl filaments. Magnified 
150 diameters. 

Fig. 21. — Dissoconch Phase 2. About two days after "set." View of trans- 
parent right valve through which the organs are seen. The right valve is less 
convex than the left, for aid in crawling. The heart (ht) is observed for the first 
time during this stage. Note the slower growth of the byssal or foot notch, which 
is one period behind the growth of the rest of the shell. Note also the increase 
in the number of gill filaments. Magnified 150 diameters. 

Fig. 22. • — Internal view of shell of scallop of same age as in Fig. 21, showing ten 
pairs of small teeth (te), which interlock to form a firm hinge. The shell is inequi- 
valved, i.e., the right valve (upper in illustration) is less concave than the left. 
Magnified 150 diameters. 

Fig. 23. — Internal view of same scallop as in Fig. 21, showing the adductor 
muscle and foot, the rest of the soft parts having been removed. Scallops of this 
age often open the shell to an angle of 90°, thus illustrating the flexibility of the 
adductor muscle. Magnified 150 diameters. 

Fig. 24. • — Dissoconch Phase 3. View of right valve of scallop about four days 
after "set," showing anatomy. The left valve projects slightly beyond the right, 
and the hinge line is inclined slightly upward. Note increased number of gill bars. 
Magnified 150 diameters. 





17 



18 




Fig. 25. — Dissoconch Phase 4. View of right valve of scallop about one week 
after "set." Note contrast between the prodissoconch (pd) or embryonic shell 
and the succeeding dissoconch growth (d). A groove has been formed by the 
growth of the byssal or foot notch (bn), which is increasing in size to correspond 
with the development of the foot. The right valve is smaller than the left. Mag- 
nified 37 V^ diameters. 

Fig. 26. — - View of left valve of same scallop as in Fig. 25, showing the lines of 
growth and the formation of the pseudo-ear, which corresponds to the location of 
the byssal notch. Magnified 37^'2 diameters. 

Fig. 27. — Same scallop as in Fig. 25, with foot extended. Anatomy shown 
through transparent left valve. Note increased number of gill filaments (ig) and 
the well-defined heart (ht). The byssal gland (bg) and cleft have become promi- 
nent on foot. The knob-like projections on the mantle are the beginnings of the 
tentacles (t). Magnified 37 V^ diameters. 

Fig. 28. — View of soft parts of slightly older scallop of Phase 4. Note the 
nine small tentacles ("t), the two eyes (e) and the fourteen gill filaments (ig). Mag- 
nified 37^^ diameters. 

Fig. 29. — Dissoconch Phase 5. Anatomy shown through transparent right 
valve. This stage is characterized by one tooth in the byssal notch. The scallop 
is represented as lying in a resting position, with mantle and foot retracted. Note 
the formation of eight secondary tentacles between the primary, the relative posi- 
tion of the eyes (e) and the tenatcles (t), and the beginning of the outer gills (og). 
Magnified 37'/^ diameters. 

Fig. 30. — View of same scallop as shown in Fig. 29, as seen through left valve, 
with mantle (m) expanded and foot (f) extended. The edges of the mantle have 
joined posteriorly to form a pseudo-siphon (ps), through which water is expelled 
from the shell. The byssal gland (bg) has a prominent position on the long foot 
(f). Magnified 37% diameters. 

Fig. 31. — Dissoconch Phase 6. Characterized by two teeth on the byssal 
notch. View of anatomy through right valve. Tertiary tentacles are developing 
on the edge of the mantle, which is partially extended. At this age the scallop 
has about twenty-two inner (ig) and ten outer (og) gill filaments. Magnified 37% 
diameters. 

Fig. 32. — Scallop of same phase as in Fig. 31, lying on left valve in an unnatural 
position. The animal has extended his foot (f) for the purpose of turning over. 
The eyes (e), tentacles (t) and guard flap (mf) can be seen on the edge of the mantle. 
Magnified 37'/^ diameters. 



Fig. 33. — - Early plicated stage. View of the right or lower valve. Note 
the smooth prodissoconch (pd) and dissoconch (d) areas, with the beginning of 
the sixteen plications (pi) of the adult. There are four teeth (te) on the byssal 
notch. Actual size, 1.25 millimeters (%n of an inch). 

Fig. 34. — Same scallop as in Fig. 33, viewed from left or upper valve. Actual 
size, 1.25 millimeters (^/'20 of an inch). 

Fig. 35. — View of the anatomy of a slightly older scallop, size, 1.4 millimeters 
(Ms of an inch), afe seen through the right valve. Note primary, secondary and 
tertiary eyes (e) and tentacles (t). The outer gill (og) has about twenty-five fila- 
ments, and begins to resemble the inner gill (ig). 

Fig. 36. — View of right or lower valve of same scallop as in Fig. 35. Note 
the five teeth (te) on the byssal notch (bn) and the beginning of the "ears" (er). 
The two teeth back of the external border of the byssal groove are older, and have 
rounded rather than the pointed ends of the last formed teeth. The valves have 
become nearly equal, the hinge line straight, and the byssal groove (bg) can be 
traced back to the asj'mmetrical prodissoconch. Actual size, 1.4 millimeters (■'/is 
of an inch). 

Fig. 37. — View of upper left valve of same scallop as in Figs. 35 and 36. Actual 
size, 1.4 millimeters {Vis of an inch). 




33 





"35 





36 



37 



Fig. 38. — Dorsal view of Pecten in plicated stage, showing umbones and 
hinge Une. The left valve is deeper than the right. The prodissoconch (pd) is 
sharply marked o£F, the amotint of separation between its two valves being well 
shown. Magnified 32 diameters. 

Tig. 39. — Plicated stage. A 2. 1.5-niilliineter scallop magnified 32 diameters. 
View of comer of right valve, showing groove and notch. Xine teeth (te) can be 
seen in the byssal area, six of which are within the external border of the groove. 
There is a second furrow dorsal to the byssal groove, and a serrated structure near 
the hinge line of seven sharply pointed teeth, which possibly may be an indi^'idual 
variation. 

Fig. 40. — Posterior view of scallop in the plicated stage, showing that the 
shell has become more nearly equivalvular. The plicated (pi) and dissoconch (d) 
areas are sharply differentiated. Magnified 32 diameters. 

Fig. 41. — Prismatic structure of right valve of dissoconch shell highly mag- 
nified. This structure is not found on the left valve, or on either valve of the adult. 
Magnified -340 diameters. 

Fig. 42. — Foot of 2.>-inilIiineter (about 1 inch) scallop, showing cleft (fc), disc- 
like tip, byssal gland (bg) and groove (fg). Magnified 7 diameters. 

Fig. 43. — Byssus of scallop of dissoconch stage after having been cast off by 
the animal; distal (di) or attached end; proximal (pr) or gland end. Magnified 
5 diameters. 

Figs. 44-46. — Stages showing the development of the tenacle. Fig. 44 rep- 
resent; the first appearance, Fig. 4-5 further development, and Fig. 46 the tip of 
a completely formed tenacle. The tenacles on the edge of the mantle are used as 
sensorj-, clinging and crawUng organs. Magnified 110 diameters. 

Fig. 47. — Scallop (4 to 5 millimeters in size; drifting just below the surface 
of water in aquarium (see page 60). Xote the extended tentacles (t), open shell 
and the reverse position, with right valve uppermost. Magnified 5 diameters. 

Fig. 48. — .Scallop (1..5 millimeters in sizej attached to eel grass by a two- 
stranded byssus (h), formed during the night, ilagnified 7 diameters. 




-,-pa- 










47 




Figs. 49-51. — Turning Over. — When lying on the left valve, as in Fig. 49, 
the small scallop appears uneasy, as its normal position is on the right. After a 
few minutes it thrusts out its foot, waves it around, as if seeking a foothold, and 
finally applies the cleft tip to the bottom of the glass dish with a twisting motion. 
By this movement the shell is so pulled that the hinge line rests upon the bottom 
(Fig. 50), and the scallop pries itself over, naturally falling into its normal posi- 
tion on the right valve. 

Figs. 52-54. — These figures illustrate the strength of the byssal thread, which 
permits the revolving of a young scallop at least 360° without breaking the strands. 
The scallop is shown as it is turned around on its attachment by a pencil. 

Figs. 55-57. — Crawling. — In Fig. 55 the young scallop, lying on its right 
valve, has extended its foot, the tip of which is firmly set on the bottom. Fig. 56 
shows the tipping of the shell forward by the contraction of the foot. Fig. 57 
shows the completion of the movement, by which the animal has traveled three- 
quarters of its length, and the extension of the foot for a second pull. The action 
of the foot is strengthened by the clapping of the valves, which sends out a current 
of water from the posterior side of the shell. 

Figs. 58-60. — Spinning the Byssus. — In Fig. 58 the foot is extended, with 
tip and byssal gland touching the bottom of the glass dish, in order to attach the 
byssal thread. Fig. 59 represents the spinning or drawing out of the byssal thread 
by the retraction of the foot toward the shell, and Fig. 60 shows the young scallop 
attached by one thread, while the foot is in the act of extension for the purpose 
of attaching a second strand at a point slightly removed from the fixation of the 
first. The spinning of a single thread occupies about two minutes. 

Figs. 61, 62. — Swimming. — Swimming is accomplished by the alternate 
expulsion of water first from one "ear," as B, and then from the other, as D, which 
forces the scallop ahead by a series of zigzag jerks or tacks in the directions C 
and E respectively. (These two figures are from the illustrations of Prof. R. T. 
Jackson, Figs. 8, 8a, Plate XXVIII. , Memoirs Boston Society Natural History, 
Vol. IV.) 

Figs. 63, 64. — These figures illustrate a manner of avoiding enemies. In 
Fig. 63 the scallop, when approached by a pencil at the free edge, darts quickly 
away in the direction of the arrow by violently expelling water from its ventral 
border. Darts can be likewise made in either a forward or backward direction, 
as shown in Fig. 64. 



Fig. 65. — External view of the two valves of the scallop. Left valve: A, 
anterior border; P, posterior border; D, dorsal border; V, ventral border (free 
edge) ; HH, hinge line; AP, width; DV^, height. Right valve: U, umbo; B, byssal 
notch; E, ears; R, ridge; F, furrow. 

Fig. 66. — Shows the method of recording the growth of individual specimens 
and of obtaining data upon the migratory habits of the scallop. A small hole was 
bored through the "ear" close to the hinge line with an awl. A numbered copper 
tag was attached by a fine wire. 

Fig. 67. — Generative gland: ov, ovarj^- t, testis; ep, ciliated epithelium on 
surface of visceral mass; glc, gland cells; bm, basement membrane; ct, tissue of 
irregular cells beneath epithelium; fep, follicular epithelium; d, ciliated ducts, the 
one in the testis containing spermatozoa, and on its walls a gland cell being shown; 
bv, blood vessel. (This illustration is a copy of a drawing by James L. Kellogg, 
produced as Fig. 71, Plate LXXXIX., Bulletin, United States Fisheries Commis- 
sion, 1890, and is published with the consent of Dr. Kellogg. Unfortunately, in 
the reduction much of the fine detail of the original has been lost.) 

Fig. 68. — The oyster drill (Urosalpinx cinerea). An enemy of the scallop, which 
bores a fine hole through the shell and feasts upon the soft parts. Cases contain- 
ing the eggs of this moUusk are shown on the right. Life size. 

Fig. 69. — Scallop Food. — Typical diatoms found in Massachusetts waters, 
(a, b, c) Navicula, (d, e) Pleurosigma, (f) Nitzschia, (g) Melosira, (h) Chcetoceras, 
(i) Cyclotella, (j) Licmophora. Magnified 200 diameters. 

Fig. 70. — A starfish opening a scallop by slowly dragging the valves apart by 
means of small, sucker-like feet on the lower side of each of the five rays or "arms." 
When the valves are forced apart the starfish rolls out its stomach, which envelops 
the soft body of the scallop. Digestive juices are poured forth and the food is 
digested outside the body of the starfish. This creature is the most destructive 
natural enemy of the scallop, and in certain localities has made serious inroads. 
It is best killed by steaming or bringing ashore. 

Fig. 71. — Diagram of the wire cages in which scallops were suspended from 
the raft at Monomoy Point. The cage consists of a framework of wood covered 
with 13^-inch mesh wire netting. 

Fig. 72. — Plankton net, made of silk bolting cloth, used to catch the swim- 
ming shellfish larvge. The net is towed through the water behind a rowboat. 




66 










>,\ 



68 



a ^ e ? M g 




70 









71 




In general, the organs of Pecten lie at three different layers, viz., valve, mantle 
and gills. Figs. 73, 74 and 75, which are one and one-quarter times the natural 
size, represent the views disclosed as each of these layers is successively cut away. 

Fig. 73. — View of Pecten with left valve removed. The gills (g), liver (1) 
and palps (Ip) are represented in dotted lines as they are seen through the trans- 
parent mantle. As the left lobe of mantle (m) has been detached from the shell, 
it has contracted. The right mantle (m) lobe is shown fully extended. 

Fig. 74. — View of Pecten with left valve and mantle removed, showing gills 
(g), palps (Ip), foot (f) and liver (1). 




f*. 



73 



im — — 




^^p^ 



— t 



74 



Fig. 75. — View of Pecten with left valve, mantle (m) and gUls (g) removed, 
showing the heart (ht), visceral mass (vm) and reproductive organs. 
Pig. 76. — View of Pecten, showing the digestive sj'stem. 



— pa. 




75 




I - 



a 



— ~-m 



76 



Pig. 77. — Changes in form of shell. A series of drawings illustrating the 
changes from the early veliger (the first shell), which is Mo of a millimeter in size, 
to a 2-millimeter scallop. Note (a) change from fiat-hinged veliger (1) to the pro- 
dissoconch (2), with prominent umbones; (6) return to a straight hinge (3), width 
greater than height; (c) width and height become equal (8); (d) formation of 
" ears" (10). 



Fig. 78. — Map of the Massachusetts coast, showing the distribution of the shal- 
low-water scallop (Pecten irradians). The scalloping grounds are indicated by the 
black areas. 



PfiOVlNCETOVN 




WEULFLEET 



78 



Pig. 79. — Plan of biological raft used at Monomoy Point for growth experi- 
ments and spat collecting. The raft, 20 feet long by 10 feet wide, provided with 
a central well and four trap-doors, was anchored in the Powder Hole in 20 feet of 
water. Wire cage^ and wooden boxes were suspended at various depths from the 
raft. Many kinds of mollusks were caught and raised in these spat boxes. The 
raft proved particularly useful in the study of the post-embryonic life history, as 
the scallops "set" in large numbers on the boxes, cages and ropes, where speci- 
mens could be obtained in all stages of development for laboratory examination. 
Also, many interesting growth experiments upon the quahaug, scallop and clam 
were conducted in the sand boxes. 



Fig. 80. — Type of pen used in determining the rate of growth of the scallop. 
The sizes ranged from 40 to 400 square feet. The posts were made of 2 by 3 foot 
joists, fixed in the soil and placed at sufficient intervals to hold the netting firmly 
in position. Wire netting (134 -inch niesh) and old seines of a suitable height were 
stretched around the posts. 




OQ 



Fig. 81. — Chart of the daily temperatures for the month of June, taken at the 
Powder Hole at Monomoy Point in 1906 and 1907. The average of the daily 
temperatures at 1, 10 and 20 feet, taken at 6 a.m., 12 m. and 6 p.m., is given. The 
great irregularity of the curve is due to the fluctuation of this small body of water 
with changes in the temperature of the air. The season of 1907 was nearly two 
weeks behind that of 1906, as during the early part of June the temperature was 
from 8° to 10° colder, but by June 19 the two became approximately the same 
as is shown by the intersection of the curves on the chart. The principal fact 
shown by the plot is the location of the "spawning" temperature, or the tempera- 
ture necessary for spawning. In 1906 the scallops first spawned on June 12, in 
1907 on June 21. In each case spawning did not occur until the water reached the 
temperature of 61%°, although there was Tiine days' variation between the two 
years. 

Fig. 82. — The Food Value of the Scallop. — The relative proportion, by 
weight, of the various parts of the average scallop is graphically represented by a 
series of rectangles, corresponding to (1) the total weight, 1.5 ounces, or 100 per 
cent.; (2) total non-edible part, 1.23 ounces, or 82.23 per cent., which includes 
both shell and non-edible soft part; (3) shell, .74 of an ounce, or 49.43 per cent.; 
(4) non-edible soft part, .49 of an ounce, or 32.8 per cent.; (5) actual food, .27 of 
an ounce, or 17.77 per cent. 













































































































































































































































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1 2. 3 H- 5 fc 7 a 1 10 II IJ, 13 IH- 15 lb 17 1% 11 &0 J.I %%. U 24- 25 Rfc ^7 28 21 30 

JUNE 
81 









TOTAL SCALLOP NON-EDlBLt 
PART 
1.5 oz. 1.23 oz, 

10070 

FOOD 



SHELL NON-EDIBLE MEAT EDIBLE HEAT 
HH-oz. H-^oz. .S7oz. 

»a.i3/. 4-^H-37» 32.80yo n.T?/" 

VALUE OF SCALLOP 
82 



Fig. 83. — The Spawning Months. — The spawning season lasts from the 
second week in June to the middle of August. Tliis period is represented by the 
shaded portion. 

Fig. 84. — The Growing Months. — The scallop increases in size of shell 
only during the summer months, as during the winter growth ceases. The shaded 
portion represents the period of growth. 

Fig. 85. — The Relative Value of the Growing Months. — The scallop 
does not increase with equal rapidity during the seven months of growth. The 
relative value of these months is graphically represented in terms of the increase 
in volume during each month for a standard scallop. The slow growth during 
June and July, as represented by the short columns, roughly corresponds to the 
spawning season, and the decrease in growth is probably due to that cause. 




JAN. FEB. "tlAR. APRIL MAY JUNE JULY A U g. SEPT. OCT. NOV. DEC. 

SPAWNING MONTHS 

83 




JAN. FEB. MAR APRIL MP^Y JUNE JULY AUg SEPT. OCT, NOV- DEC. 

GROWING MONTHS 

84 



^ 



JU.ME JULY 



Aug. 



SEPT 



OCT 



RELATIVE 
OF GROWING 



VALUE 
MONTHS 



85 



^ 



Fig. 86. — Age and Growth. — As the scallop becomes larger the rate of 
growth, both in actual increase and gain in volume, becomes less. The three 
columns represent the comparative gain in volume of (1) "seed" scallops (^ of an 
inch) of the 1906 set, 200 per cent. ; (2) fourteen-month scallops of the 1905 set, 
25 per cent.; (3) twentj^-six month scallops of the 1904 set, 12 per cent., under 
the same conditions. 

Fig. 87. — Current and Growth. — The three columns represent the volu- 
metric growth, for a definite period, of scallops in good, medium and poor currents, 
and are formulated from measurements made at Stage harbor, Chatham, in 1906- 
07. At the mouth of the harbor is a large eel-grass flat, extending from the shore 
to the channel. The flat was arbitrarily divided into three areas, according to the 
circulation of water: (1) near the channel (good current) ; (2) half-way to shore 
(medium current) ; (3) near shore (poor current) ; and the rate of growth of the 1906 
set was followed in each division. These figures demonstrate the great importance 
of current in scallop growth. 

Fig. 88. — Current and Growth. — The influence of current is again illus- 
trated by comparing the volumetric growth of "seed" scallops of the same size at 
(1) the raft, Monomoy Point (good current), 662 per cent.; (2) Stage harbor, 
Chatham (medium current), 475 per cent.; (3) south side of Powder Hole, Mono- 
moy Point (poor current), 293 per cent.; (4) east side of Powder Hole (no cur- 
rent), 98 per cent. The comparative volumetric growth for a period of seventy-six 
days during the summer of 1906 is represented for each of these localities by the 
shaded columns. A knowledge of the relation of current to growth should prove 
valuable to the prospective scallop culturist. 




LXX>^^ 



nofo 

sLooyo 



AGE 



1 S05 

AND 

86 



GROWTH 





Good medium 

CUR RENT 



lUf(o7o 
POOR 

AND 

87 



G R O W T H 






(o(o2.y<. 4-T5 7° 


ais'A S8°/« 


GOOD MEDIUM 


POOR NONE 


CURRENT 


AND G R WT I 



88 



Fig. 89. — Temperature and Growth. — The broken line represents the 
curve of the average monthly temperature of the water during the year 1906 at 
the Powder Hole, Monomoj^ Point, and the numbers on the sides indicate the 
degrees. The other curve represents the growth of the 1905 scallop set during 
the year 1906, and the same figures which corresponded to the degrees in tempera- 
ture now stand for the size of the scallop in millimeters (25.4 millimeters equal 
1 inch). Tracing the growth of the scallop, size 34 millimeters, January 1, no 
growth is noticed until May 1, when the water assumes a temperature of about 
49° F. During the month of May there is a rapid growth, which slackens during 
June and July, the spawning months, as is shown by the drop in the curve, and 
is again resumed during August, September and October. The growth perceptibly 
slackens during November, and probably ceases altogether after the middle of 
the month, when the water is about 43° F. To all practical purposes the growth 
ceases November 1, at a temperature of 49° F., which is directly comparable to 
temperature of the water when growth began. May 1. Therefore, it is apparent 
that the growth of the scallop, as typified by shell formation, depends upon the 
temperature of the water, at least 45° F. being necessary for growth. The ces- 
sation of growth is not due to any decided fall in the food supply but rather to the 
inactivity of the scallop, which becomes sluggish in cold water. 



Growth (Millimeters). 



May 1, 
June 1, 
July 1, 
August 1, 



34.00 
39.71 

42.12 
45.10 



September 1, 51.00 

October 1 56.80 

November 1, 62.28 

December 1 62.90 



Fig. 90. — The plotting shows the comparative growth of large and small 
scallops of the same age during their second summer. Division B (38.50 milli- 
meters) by the end of the season has gained the greater part of the difference at 
the start between it and Division A (49.50 millimeters), reducing the margin from 
11 to 3.27 millimeters. These scallops were confined in the same pen, and num- 
bered Division A 125, Division B 200. This tendency perhaps accounts for the 
uniformity in size of scallops in any particular locality at the end of the second 
summer's growth, when the scallop is ready for market. 

Growth (Millimeters) . 





A. 


B. 




A. 


B. 


May 1, . 


49.50 


38.50 


September 5, . 


56.72 


51.90 


June 1 


52.25 


43.25 


September 25, . 


59.79 


55.67 


July 10, . . . ■ . 


53.55 


46.25 


November 3, . 


62.88 


59.46 


August 1, . 


54.60 


47.85 


November 22, . 


63.00 


59.73 

















A 






















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JAN. FEB. MAR. APR. MAY JUNE JULY Kug, SEPT. OCT. NOM. DEC. 

89 



~J/ : 



JAN. FEB. MAR. APR. MAY JUNE 30L\ AUg. SEPT. OCT. NOV, DEC. 

90 



75 



70 



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to 



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50 



'^5 



35 



15 



TO- 



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50 



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35 



30 



Fig. 91. — The curve represents the growth of the average Massachusetts scal- 
lop from 1905 to 1907. Notice the rapid growth from July to December in 1905, 
and the complete cessation during the winter months. During the second summer 
comes another period of rapid growth, which ceases about Dec. 1, 1906. The normal 
life of these scallops ends some time in March or April, 1907, but a few often pass 
the two years' mark. The growth of these old scallops is represented by the broken 
line in the diagram, summer growth starting about May 1. The figures on the 
right represent the size of the scallops in millimeters (25.4 millimeters equal 1 inch). 



Average Scallop {Millimeters) . 



Aug. 1, 1905 2.00 

Sept. 1, 1905, 12.66 

Oct 1 1905, 23.20 

Nov. 1, 1905 33.11 

Dec. 1, 1905 34.24 

May 1, 1906 34.24 

June 1, 1906 39.51 

July 1, 1906, . . . . . . 41.77 



Aug. 1, 1906 44.57 

Sept. 1, 1906 50.08 

Oct. 1, 1906, 55.51 

Nov. 1, 1906 60.68 

Dec. 1, 1906, 61.27 

May 1, 1907, 61.27 

June 1, 1907, 63.93 

July 1, 1907, 65.07 



Fig. 92. — The three curves. A, B and C, represent the growth of the average 
scallop in the three localities of Buzzard's Bay, Cape Cod and the islands of 
Martha's Vineyard and Nantucket, respectively. For convenience, the start is 
considered as uniform, although there is several days' difference in the spawning 
season. The difference in growth at the various dates can be determined by refer- 
ring to the figures on the right, which represent the size of the scallop in milli- 
meters (25.4 millimeters equal 1 inch). 



Growth {Millimeters) . 



Date. 


C. 

The Islands. 


B. 

The Cape. 


A. 

Buzzard's Bay. 


August 1, 


2.00 


2.00 


2.00 


September 1 
















10.48 


12.52 


15.03 


October 1 
















18.93 


22.88 


27.86 


November 1 
















26.71 


32.65 


39.97 


December 1 
















27.60 


33.76 


41.35 


May 1 
















27.60 


33.76 


41.35 


June 1 
















33.44 


39.03 


46.27 


July 1 
















35.90 


41.25 


48.34 


August 1 
















38.95 


44.00 


50.92 


September 1 
















45.98 


49.43 


56.01 


October 1 
















50.91 


54.28 


61.03 


November 1 
















56.50 


59,83 


65.73 


December 1 
















57.13 


60.40 


66.27 


May 1 
















57.13 


60.40 


66.27 


June 1 
















60.01 


63.04 


68.73 


July 1 
















61.28 


64.15 


69.77 





















































































































































































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Fig. 93. — Graphic representation of the growth of the average scallop and 
its gain in volume. Starting September 1 with 1 bushel of %-inch scallops, the 
increase in volume is represented on the right in terms of bushels, corresponding 
to the different sized scallops on the left: (1) two-month scallop, .5 of an inch, 
1 bushel; (2) three-month scallop, .91 of an inch, 7.3 bushels; (3) five-month scal- 
lop, 1.34 inches, 26.5 bushels; (4) thirteen-month scallop, 1.75 inches, 62 bushels; 
(5) seventeen-month scallop, 2.41 inches, 185.6 bushels. The scallops are drawn 
one-half actual size. This rapid increase shows the benefit of preserving the " seed ' ' 
scallop, as the yield in large scallops will more than repay the fisherman for his 
foresight. 




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Fig. 94. — ■ Nassa obsoleta (the little black winkle of the tide flats) devouring 
a scallop. These little scavengers swarm over the scallop. Occasionally one is 
active enough to get between the valves, forming a wedge which permits the entrance 
of others, which quickly consume the scallop. Owing to the alertness of the scal- 
lop and its different habitat (Nassa usually being found on the tide flats) little 
damage is done. 



Fig. 95. — The oj'ster drill (Urosalpinx cinerea) boring the shell of a scallop. 
Five drills were found on this specimen, but one rolled off when the photograph 
was taken. The drill bores a fine hole through the shell by means of a ribbon-like 
tongue lined with saw-like teeth, and then sucks out the contents. 



Fig. 96. — Spat boxes, lowered from the raft at Monomoy Point, after having 
been down for the summer. Notice the quantity of barnacles and silver shells 
(Anomia) which have collected on the outside. Inside these boxes heavy sets of 
clams and quahaugs were obtained, while on the outside were found numbers of 
young scallops, which were removed before the photograph was taken. 



Fig. 97. — Method of recording the spawning of the scallop. W. G. Vinal, 
following the spawning of individual scallops, placed them in separate glass dishes. 
In this artificial way the time and manner of spawning could be determined, and 
the eggs obtained for artificial fertilization. Spawning was accomplished by rais- 
ing the temperature of the water. 



Pig. 98. — Young oysters, about three months old, attached to the upper valve 
of living scallops, taken at Wellfleet in October, 1908. As these oysters increase 
in size they prove detrimental to the welfare of the scallops, and finally may cause 
their death. 



Fig. 99. — Scallops over one year old, as shown by the formation of the annual 
growth line, which is caused by cessation of growth during the winter months. 
Any scallop which does not possess this annual growth line is less than one year 
old, and is a "seed" scallop. The present legal definition of a "seed" scallop is 
based on the annual growth line, as its absence indicates that the animal has not 
as yet reached its spawning season, and is, therefore, an immature animal. 



Pig. 100. — "Seed" scallops, with a small amount of white worm tube (Serpula) 
attached to the shell. These scallops have not yet spawned, and, for the future 
welfare of the scallop fishery, should be protected until they have passed the spawn- 
ing period, which occurs when the scallop is one year old. The capture of these 
immature scallops is a decided menace to the fishery, and is forbidden by law. 



Fig. 101. - — Variation in size of scallops. The two on the left are fifteen months 
old, while the two on the right are "seed" scallops three months old. The dif- 
ference in size in scallops of the same age, especially in different localities, renders 
impossible the definition of a "seed" scallop by means of a size limit. 



Fig. 102. — Young, yearling and two-year-old scallops. The small scallops 
on the left are three months old "seed; " those in the center are eleven months 
old, and have a growth line near the edge of the shell; while the large scallops on 
the right are twenty-three months old, and have two growth lines, the second 
being close to the edge of the shell. About one-half life size. 



Fig. 103. — The scallop on the left, as indicated by the arrow, has been killed 
by the oyster drill, which has pierced the shell with a fine hole. A year-qld oj^ster 
is attached to the scallop in the center, while a Crepidula (quarterdecker) has 
fastened on the scallop on the right. 













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Fig. 104. — These scallops show two or three lines which indicate temporarilj^ 
arrested growth. A careful distinction should be made between such lines and the 
annual growth line, which is caused by the non-growth of the scallop during the 
winter months, appearing about May 1. 



Fig. 105. — Instrument used for measuring the scallops. The scallop is passed 
down the triangle until it touches on both sides, where the figures indicate its 
length in millimeters (25.4 millimeters to an inch). The instrument posses.?es the 
advantage of speed and accuracy for quick measuring, as many as 1,200 measure- 
ments being possible in an hour. 



Fig. 106. — The two scallops, each fourteen months old, illustrate the dif- 
ference in growth between localities with good and poor circulation of water. The 
scallops situated in the "current" receive more food than in the stUi water, and 
naturally have a faster growth, as is shown by the greater size of the "current" 
scallop. 



Fig. 107. — The Scallop Pusher. — This implement consists of a wooden 
pole, from 8 to 9 feet long, attached to a rectangular iron framework, 3 by l-^'^ feet, 
fitted with a netting bag 3 feet in depth. The scalloper, wading in the shallow 
water, gathers the scallops from the flats by shoving the pusher among the eel 
grass. The photograph shows the correct position of the pusher in operation. 
Only a small part of the pole is shown. 



Pig. 108. — Scallop Dredge, — "The Scraper." — This implement has the 
form of a triangular iron framework, with a curve of nearly 90° at the base, to form 
the bowl of the dredge. On the upper side a raised crossbar connects the two arms, 
while at the bottom" a strip of iron 2 inches wide extends across the dredge. This 
narrow strip acts as a scraping blade, and is set at an angle so as to dig into the 
soil. The top of the net is fastened to the crossbar and the lower part to the blade. 
The usual dimensions of the dredge are: arms, 2y2 feet; upper crossbar, 2 feet; 
blade, 2^^ feet. The net varies in size, usually running from 2 to 3 feet in length 
and holding between 1 and 2 bushels. Additional weights can be put on the cross- 
bar when the scalloper desires the dredge to "scrape" deeper. A wooden bar 2 
feet long buoys the net. The scraper used at Nantucket has the entire net made of 
twine, whereas in other localities the lower part consists of interwoven iron rings. 



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Fig. 109. — Scalloping boats between the wharves at Nantucket. The cat- 
boats are moored in this fashion after the day's dredging. 
Fig. 110. — The start. Leaving for the scalloping grounds. 



Fig. 111. — The scalloping fleet at work on the beds. 
Fig. 112. — "Dredging." 



Fig. 113. — Emptying the contents of the dredge on the "culling" board, where 
the scallops are separated from the eel grass and other debris. 
Fig. 114. — "Culling." 



Fig. 115. — Landing the catch on the wharf. 

Fig. 116. — Carrying the scallops to the shanties, where they are opened. 



Fig. 117. — Shell heap outside the shanties at the end of the season. 

Fig. 118, — The finished product, packed in kegs, ready for shipment to market. 

Note. — Figs. 109-118 are from an excellent series of photographs furnished 
by Mary H. Northend, Salem, Mass. 












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®l)e (Homtnomoeoltl) of iHtt00acf)ii0ett0. 



A REPORT 



The Scallop Fishery 



Massachusetts, 



INCLUDING THE HABITS, LIFE HISTORY OF PECTEN IBRADIANS, 

ITS RATE OF GROWTH, AND OTHER FACTS OF 

ECONOMIC VALUE. 




BOSTON: 

WRIGHT & POTTER PRINTING CO., STATE PRINTERS, 

18 Post Osticb Squaee. 

1910. 



LB N 






